Mammals Obtained by Dr. Curt von Wedel from the Barrier Beach of Tamaulipas, Mexico BY E. RAYMOND HALL University of Kansas Publications Museum of Natural History Volume 5, No. 4, pp. 33-47, 1 figure in text October 1, 1951 University of Kansas LAWRENCE 1951 UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY Editors: E. Raymond Hall, Chairman, A. Byron Leonard, Edward H. Taylor, Robert W. Wilson Volume 5, No. 4, pp. 33-47, 1 figure in text October 1, 1951 UNIVERSITY OF KANSAS LAWRENCE, KANSAS PRINTED BY FERD VOILAND, JR. , STATE PRINTER TOPEKA, KANSAS 1951 23-7414 Mammals Obtained by Dr. Curt von Wedel from the Barrier Beach ofTamaulipas, Mexico BY E. RAYMOND HALL What species of mammals occur on the "coastal island", barrier beach, ofTamaulipas? Are the closest relatives of these mammals on Padre andMustang islands of Texas, instead of on the mainland of Tamaulipas, orare the mammals on the barrier beach distinct from all others? Thesewere questions that Dr. Von Wedel of Oklahoma City and I asked ourselvesin March of 1950 when we were in southern Texas. With the aim in mind ofanswering these questions, Dr. Von Wedel arranged round-triptransportation, by air, for the two of us between Brownsville, Texas, and Boca Jesús María. The latter place is a "pass", tidal inlet, throughthe long barrier beach. The waters of the Gulf of Mexico and of thelagoon behind the beach flow back and forth with the changing tidesthrough the inlet. We arrived at Boca Jesús María on March 18, 1950, and left on March 22, 1950. Our headquarters there were in one of the four one-story buildingsimmediately north of the inlet. This place is approximately 89-1/2 milessouth, and 10 miles west, of Matamoros, Mexico. Most of our collectingwas done on the sand dunes one and one-half miles north of the buildingsbut on the evening of March 20 we made a round-trip, by boat of course, to the sand dunes on the south side of the inlet to set traps; thesetraps, and the _Dipodomys_ that were caught in them, were picked up thefollowing morning. At the time of our visit, the part of the barrier beach south of thetidal inlet was connected with the mainland. The connection was far tothe southward, according to our pilot, Mr. Kagy of Brownsville, and alsoaccording to the testimony of the Mexicans at the fishing camp where westayed on the north side of the inlet. The barrier beach which lay tothe north of the inlet extended sixty-odd miles northward to the deltaof the Río Grande and had, we were told, eight "passes, " including PasoJesús María. At the time of our visit, however, only three of thesetidal inlets were open, it was said; the five others were thought to befilled in with sand, which permitted terrestrial animals to move fromone part of the beach to another. Dr. Von Wedel and I saw two tidalinlets that were open when we were being flown back to Brownsville. [Illustration: FIG. 1. Diagram of physiographic features of the barrierbeach of Tamaulipas. Top view looking down, as from an airplane, on thebeach. Bottom view is profile. ] The long, low, sandy island, technically a barrier beach, irrespectiveof tide varied in width from a quarter of a mile to as much as a mileand was separated from the mainland by the Laguna Madre, which was fourmiles wide opposite our trapping station. To the northward the width ofthe lagoon gradually increased until, at a place thirty miles north ofour trapping station, the lagoon was almost 20 miles wide. The island was perhaps four feet above high tide. Superimposed on this, in places, there were sand dunes, technically barchans, so arranged thatthe end of one touched the end of the next. The tops of some were asmuch as 20 feet above high tides and the chain of these connected-duneson which we trapped was approximately a mile long. Incipient tidalinlets were frequent; they were where storm-driven waves of high tideshad broken across the island between the adjacent ends of two dunes. Thewindward side of a dune was toward the Gulf and the slope of that sidewas gentler than that on the leeward side. According to the cycledescribed by Davis (Proc. Amer. Acad. Arts and Sciences, 22:303-332, 1896) and recently figured on page 364 by Lobeck (Geomorphology, 1sted. , xii + 731 pp. , 1939, McGraw Hill Book Co. , Inc. , New York) thebarrier beach concerned was in the early part of the "Middle YouthStage". Typically, on the center of the area in the lee of a dune there was apatch of plum brush, almost five feet tall and so dense that a personcould not penetrate it. A belt of grass, 20 to 100 feet wide, surroundedthe plum brush. The grass was approximately 20 inches high. Outside thearea of grass, there were widely-spaced xerophitic shrubs which grewalso on the dunes. The diagram (fig. 1) shows these prominent featuresas a person might see them if he looked directly down from an airplane. We obtained specimens of the spotted ground squirrel (_Citellusspilosoma_), Ord kangaroo rat (_Dipodomys ordii_), hispid cotton rat(_Sigmodon hispidus_) and black-tailed jack rabbit (_Lepuscalifornicus_). Tracks and other sign of the coyote (_Canis latrans_)were seen. So far as we could ascertain, by our own investigations andfrom our Mexican hosts at the fishing camp, no other kinds of nativemammals lived on the island. The ground squirrel and kangaroo rat werefound by us on only the sandy areas where there were xerophitic shrubs. The cotton rat was found only in the grass. The jack rabbit and coyoteranged over the whole of the island excepting the areas of plum brush inwhich we saw no sign of any mammal. To answer the second of our initial questions: The affinities of themammals of the barrier beach of Tamaulipas are approximately equallydivided between those of the mainland and those of Padre Island. Theground squirrel is indistinguishable from the subspecies which occursboth on the mainland and Padre Island to the northward; the other threekinds of mammals of which we obtained specimens prove to besubspecifically distinct from any previously named kinds and seem to beconfined to the off-shore beach. Accounts of these four mammals and of apreviously unnamed subspecies of kangaroo rat on Mustang Island, Texas, follow. Citellus spilosoma annectens (Merriam) Spotted Ground Squirrel 1893. _Spermophilus spilosoma annectens_ Merriam, Proc. Biol. Soc. Washington, 8:132, December 28, type from "The Tanks, " 12 mi. From Point Isabel, Padre Island, Texas. 1904. [_Citellus spilosoma_] _annectens_, Trouessart, Catalogus Mammalium . .. , p. 340. Thirteen specimens (Nos. 35441-35453) were collected. All are from thenorth side of the tidal inlet. Although the ground squirrels were easilytrapped, it was difficult to obtain a perfect skin because the gulls(_Larus_ sp. ) pulled the skin off of the distal part of the tail as soonas a squirrel was secured in a trap. The specimens seem not to differfrom Texan specimens from the type locality and Mustang Island. Dipodomys ordii parvabullatus new subspecies Ord Kangaroo Rat _Type. _--Male, adult, skull and skin, No. 35454, Mus. Nat. Hist. Univ. Kansas, from island, 88 miles south and 10 miles west of Matamoros, Tamaulipas, Mexico; obtained 19 March 1950 by E. R. Hall and Curt vonWedel; original No. 6778 E. R. Hall. _Range. _--Islands along coast of Tamaulipas, Mexico. _Diagnosis. _--Size small (see measurements). Color pale; entire dorsalsurface Light Ochraceous-Buff (Capitalized color terms according toRidgway: Color Standards and Color Nomenclature, Washington, D. C. , 1912), purest on sides and flanks, upper parts lightly suffused withblack; cheeks white; plantar surfaces of hind feet, dorsal and ventralstripe of tail, and anterior face of ear brownish. Skull small; auditorybullae smaller (actually and relative to remainder of skull) than in anyother known kind of _Dipodomys_, excepting the one from Mustang Island, Texas (named beyond) in which the breadth is approximately the same;rostrum and interorbital region narrow. _Comparisons. _--From _Dipodomys ordii sennetti_ (Allen), of themainland of Texas, _D. O. Parvabullatus_ differs in: Color paler onpigmented areas; white areas more extensive; skull smaller, in all partsmeasured, except the nasals which are slightly longer. From _Dipodomysordii compactus_ of Padre Island, Texas, _D. O. Parvabullatus_ differsin: Tail and hind foot shorter; skull smaller in all parts measured, especially so in breadth across maxillary processes of zygomatic arches. _Remarks. _--_D. O. Parvabullatus_ resembles _D. O. Sennetti_ in externalproportions and _D. O. Compactus_ in cranial proportions. No difference was detected between specimens from the two sides of thetidal inlet 89 miles south of Matamoros. Only one of the 14 specimens isof the light color phase (upper parts Cartridge Buff). This palespecimen is from the north side of the inlet. The brownish stripe on theventral side of the tail is absent on the distal two-fifths of the tailand the specimens are uniform in this respect. On the occlusal surfacesof the cheek-teeth, the enamel surrounding the dentine is incomplete onboth the lingual and labial sides of the teeth of five individuals andis incomplete on the labial side of some of the teeth of a sixthspecimen. In the snap traps, all of which were baited with rolled oats, more thantwice as many land crabs as kangaroo rats were taken. Judging fromtracks in the sand, land crabs greatly outnumbered kangaroo rats. Theparietal bones in two of the 13 skulls are much eroded by some parasite(seemingly nematode worms) and in one of these two specimens the roof ofthe left tympanic cavity is perforated. As regards life-zones, theoccurrence of _Dipodomys ordii_ in the lower part of the Lower SonoranLife-zone on the off-shore beach 88 and 90 miles south of Matamoros islow zonally and perhaps is at or near the zonal margin of the range ofthe species. The crabs and worms conceivably are two of theenvironmental features inhospitable to the rats. _Specimens examined. _--Total, 14, all from Tamaulipas, Mexico, asfollows: 88 mi. S and 10 mi. W Matamoros, 7; 90 mi. S and 10 mi. WMatamoros, 7. When Setzer (Univ. Kansas Publ. , Mus. Nat. Hist. , 1:473-573, December27, 1949) reviewed the subspecies of _Dipodomys ordii_ he lackedspecimens of _Dipodomys ordii compactus_ from the type locality or fromanywhere else on Padre Island. He used as representative of _D. O. Compactus_ specimens from Mustang Island, Texas, the island nextnortheast of Padre Island. Through the courtesy of Mr. Stanley P. Young, Dr. Hartley H. T. Jackson and Miss Viola S. Schantz, of the UnitedStates Biological Surveys Collection, I have examined topotypes of _D. O. Compactus_ from Padre Island. This examination discloses that thekangaroo rats on Padre Island and Mustang Island are significantlydifferent. Those from Mustang Island may be named and described asfollows: MEASUREMENTS (IN MILLIMETERS) OF ADULT MALES OF FOUR SUBSPECIES OFDIPODOMYS ORDII Key:A Total length F Breadth across maxillary archesB Length of tail G Width of rostrumC Length of hind foot H Length of nasalsD Greatest length of skull I Least interorbital widthE Greatest breadth across bullae J Basilar length---------------------------------------------------------------------- _D. O. Largus_, type locality (K. U. ) A B C D E F G H I JMean (9) 226 117 35. 8 36. 3 21. 5 19. 2 3. 6 13. 7 12. 6 23. 2Maximum 241 128 37 37. 2 22. 0 19. 9 3. 7 14. 2 13. 9 23. 9Minimum 212 105 35 35. 2 20. 7 18. 6 3. 5 13. 5 11. 6 22. 3---------------------------------------------------------------------- _D. O. Compactus_, type locality (U. S. N. M. ) A B C D E F G H I JMean (10) 230 126 37. 7 36. 6 22. 1 20. 0 3. 8 14. 0 12. 5 23. 8Maximum 241 135 40 37. 8 23. 2 21. 4 4. 0 14. 5 13. 1 24. 4Minimum 208 118 35 35. 5 21. 6 19. 2 3. 6 13. 1 11. 3 23. 1---------------------------------------------------------------------- _D. O. Parvabullatus_, type locality and 2 mi. S of same (K. U. ) A B C D E F G H I JMean (7) 216 111 35. 9 36. 4 21. 7 19. 6 3. 6 13. 8 12. 1 23. 0Maximum 222 113 37 36. 9 22. 1 20. 7 3. 8 14. 2 12. 5 23. 5Minimum 210 109 34 35. 9 21. 3 19. 1 3. 3 13. 4 11. 6 22. 1---------------------------------------------------------------------- _D. O. Sennetti_, 2 mi. S Riviera, Texas (after Setzer, op. Cit. :565) A B C D E F G H I JMean (5) 218 112 35. 8 37. 2 23. 4 20. 1 4. 0 13. 6 13. 1 24. 2Maximum 222 115 38 38. 2 24. 1 20. 7 4. 3 14. 4 13. 2 24. 6Minimum 208 104 34 36. 3 23. 0 19. 4 3. 8 13. 0 12. 6 23. 8---------------------------------------------------------------------- Dipodomys ordii largus new subspecies Ord Kangaroo Rat _Type. _--Female, adult, skull and skin, No. 27234, Mus. Nat. Hist. , Univ. Kansas, from Mustang Island, 14 mi. SW Port Aransas, AransasCounty, Texas; obtained 30 June 1948 by W. K. Clark; original No. 543. _Range. _--Known from Mustang Island only. _Diagnosis. _--Size medium (see measurements). Color pale, and asdescribed for _D. O. Parvabullatus_. Skull small; auditory bullae(actually and relative to remainder of skull) smaller than in any otherknown kind of _Dipodomys_, except _D. O. Parvabullatus_ in which breadthacross bullae is approximately the same; notably narrow across maxillaryprocesses of zygomatic arches. _Comparisons. _--From _Dipodomys ordii sennetti_ (J. A. Allen) of themainland, _D. O. Largus_ differs in: Color paler on pigmented areas;white areas more extensive; skull averaging smaller except in basilarlength and length of nasals which are approximately the same as in _D. O. Sennetti_. From _Dipodomys ordii compactus_ True of Padre Island, _D. O. Largus_ differs in: Body longer; tail shorter; skull narrower acrosstympanic bullae and across maxillary processes of zygomatic arches;nasals shorter. From _Dipodomys ordii parvabullatus_ of the coastalisland south of Padre Island, along the gulf coast of Tamaulipas, _D. O. Largus_ differs in: Body and tail longer; basilar length of skullaveraging less; breadth across maxillary processes of zygomatic archesgreater; premaxillae not extending so far behind nasals. _Remarks. _--_D. O. Largus_ resembles _D. O. Compactus_ in externalproportions and _D. O. Parvabullatus_ in cranial proportions. The degreeof difference between _D. O. Compactus_ and _D. O. Largus_ is less thanbetween _D. O. Compactus_ and _D. O. Parvabullatus_. To me, the threesubspecies mentioned in the preceding sentence are indistinguishable incolor. Two of the eleven specimens of _D. O. Largus_ are of the light colorphase (upper parts Cartridge Buff) whereas all but two of the elevenspecimens of _D. O. Compactus_ are of the light color phase. Each of thecheek-teeth of the upper jaw of _D. O. Largus_ has a complete ring ofenamel around the dentine of the occlusal surface, as described bySetzer (Univ. Kansas Publ. , Mus. Nat. Hist. , 1:517, December 27, 1949)for _D. O. Compactus_. The upper dentitions of ten specimens of _D. O. Compactus_ examined by me in this respect reveal a total of only fiveteeth (in four individual animals) that have the enamel ring incomplete;one premolar and three molars are incomplete on the lingual side and onemolar is incomplete on the labial side. Two specimens from Bagdad, Tamaulipas, in the delta of the Río Grande(Nos. 116485 and 11487, U. S. N. M. , Biol. Surv. Coll. ), are referred to_D. O. Compactus_ on basis of long body and long tail. The specimens, both Light Ochraceous-Buff, are so young that not all of the enamel isworn off the crowns of the cheek-teeth. Specimens of _D. O. Compactus_, _D. O. Parvabullatus_ and _D. O. Sennetti_ of comparable age are notavailable, and it, therefore, is impossible to know whether size andshape of the skull in the population at Bagdad are the same as they arein _D. O. Compactus_ of Padre Island. _Specimens examined. _--Total, 11, all from Texas. Aransas County:Mustang Island, 14 mi. SW Port Aransas. Sigmodon hispidus solus new subspecies Hispid Cotton Rat _Type. _--Male, adult, skull and skin; No. 35468, Mus. Nat. Hist. , Univ. Kansas; from island, 88 mi. S and 10 mi. W Matamoros, Tamaulipas, Mexico; 22 March 1950; obtained by E. R. Hall and Curt von Wedel;original No. 6806 E. R. Hall. _Range. _--Known from the type locality only but probably occurring onmost of the chain of islands off the coast of Tamaulipas. _Diagnosis. _--Small; hind foot short; rostrum broad. _Comparison. _--From its nearest relative, geographically andmorphologically, _Sigmodon hispidus berlandieri_ Baird of the adjacentmainland, _S. H. Solus_ differs in smaller size, and a rostrum that isbroader in relation to the length of the skull. _Remarks. _--On the last night of our stay on the island, traps set ingrass approximately 20 inches high, yielded one pair of _Sigmodon_. Thecolor is lighter than in the average of specimens from the mainland (forinstance those from Victoria and Soto la Marina) but can be matched byselected specimens. In animals of equal age, the hind foot and basilarlength are shorter in _S. H. Solus_ than in _berlandieri_. Thebroadening of the rostrum, which occurs with advanced age, is attainedin _solus_ when the skull is yet short; the maximum breadth of therostrum in the adults is more, instead of less, than a fourth of thebasilar length. _Measurements. _--The following measurements are of specimens in whichthe occlusal face of each molar tooth is worn flat. The firstmeasurement is of the holotype followed by the corresponding measurementof a male of _T. B. Berlandieri_, No. 116466 from Camargo, Tamaulipas, in parentheses. The third measurement is that of the female from thetype locality of _S. H. Solus_ and it is followed by the correspondingmeasurement of a female of _T. B. Berlandieri_, No. 116462 from Camargo, Tamaulipas. Total length, 266 (298), --(293); length of tail, 113(135), --(137); length of head and body, 153 (163), 155 (156); length ofhind foot, 30 (35), 30 (33); basilar length of Hensel, 28. 2 (28. 9); 27. 9(29. 0); zygomatic breadth, 19. 5 (--), 19. 0 (20. 8); mastoidal breadth, 13. 9 (14. 4), 13. 9 (14. 8); greatest breadth of rostrum, 7. 2 (7. 3), 7. 8(7. 2); length of nasals, 14. 6 (14. 1), 13. 4 (14. 2); crown length of uppermolar teeth, 6. 3 (6. 1), 6. 3 (5. 9). _Specimens examined. _--Two from the type locality. Lepus californicus curti new subspecies Black-tailed Jack Rabbit _Type. _--Female, adult, skull and skin, No. 35470, Mus. Nat. Hist. , Univ. Kansas; from island, 88 miles south and 10 miles west ofMatamoros, Tamaulipas, Mexico; obtained 19 March 1950 by E. R. Hall;original No. 6783. _Range. _--Islands along coast of Tamaulipas, Mexico. _Diagnosis. _--Color pale; size small; ears short; tympanic bullae small. _Comparisons. _--From _Lepus californicus merriami_ Mearns (specimensfrom Fort Clark, Brownsville and intermediate localities), _L. C. Curti_differs in paler color, lesser size except ear that is of almost samelength and except interorbital breadth that is approximately same in thetwo subspecies; tympanic bullae notably smaller. From _Lepuscalifornicus altamirae_ Nelson, _L. C. Curti_ differs in having theblack patch on the nape less definitely divided by a median, longitudinal band of buffy color, and lesser size. Exception is to bemade for the ear and tympanic bullae, which are of approximately thesame size in the two subspecies. _Remarks. _--The subspecific part of the name _Lepus californicus curti_is proposed in honor of Dr. Curt von Wedel who shared the pleasure ofcollecting on the islands where this handsome hare lives. The specimens of _L. C. Curti_ are all females, which, in the genus_Lepus_, average larger than the males. Comparison of the measurementsrecorded below with those in the account by Nelson (N. Amer. Fauna, 29:129, 1909) may not reveal the full measure of difference in sizebetween _L. C. Curti_ and other subspecies because Nelson (_op. Cit. _)pooled males and females in obtaining the average measurements that herecords. For example, he used three males and two females of _Lepusaltamirae_ in obtaining an average (_op. Cit. _:117). The specimens of_L. C. Curti_ here recorded are thought to be of full size inasmuch asthe degree of fusion of bones in the skull, and the density of thecranial bones indicate full adulthood for each specimen. Reproductive-wise, there is no question as to adulthood; each of thefour females was pregnant. One specimen had two embryos (each 30millimeters long in crown-rump measurement) and each of the otherspecimens contained one embryo. These three embryos were 55, 60, and 105mm. Long. Three of our specimens, including the holotype, were obtained north ofthe eighth pass and the other specimen, No. 35473, was obtained a fewhundred yards south of the pass. Because the part of the barrier beachsouth of the pass was connected to the mainland, it is likely that thenewly named subspecies occurs also on the adjacent mainland; however, wehave examined no specimens of _Lepus californicus_ from the oppositemainland except from Matamoros, ninety miles to the north, and fromAltamira, approximately one hundred and fifty miles south of ourcollecting locality. A specimen from Matamoros, Tamaulipas, and severalfrom Brownsville, Texas, in size of auditory bullae, larger overall sizeand darker color clearly are _L. C. Merriami_ and not _L. C. Curti_. The small tympanic bullae of the specimens from Padre Island werecommented upon by Nelson (_op. Cit. _:149) who found smallness of bullaeto characterize many of the specimens from the eastern part of thegeographic range of _L. C. Merriami_. In the northeastern part of thegeographic range of _L. C. Merriami_, as Nelson pointed out, the smallsize of the tympanic bullae was one of several evidences ofintergradation there with _Lepus californicus melanotis_, the subspeciesnext adjacent to the north. In the light of present information, itseems that the smallness of the tympanic bullae in the specimens (3)from Padre Island may be an independent development--an adaptation toenvironmental conditions that reaches its fullest development on thesame chain of islands eighty-odd miles southward of Matamoros. Thespecimens from Padre Island, although possessing small bullae, in otherfeatures, for example, larger size of other parts, are _merriami_. The four specimens of _L. C. Curti_ are in worn winter pelage and thenew pelage is coming in on the thighs. Most of the specimens (6) of the_L. C. Altamirae_ are in the same condition of pelage. In color andcolor pattern, the two subspecies are, to me, indistinguishable exceptthat the black patch on the nape is less widely and less definitelyseparated into two parts by a median, longitudinal, band of buffy color. _Lepus californicus altamirae_ was named by Nelson (Proc. Biol. Soc. Washington, 17:109, May 18, 1904) as a black-tailed jack rabbit, _Lepusmerriami altamirae_, but was later transferred by Nelson (N. Amer. Fauna, 29:124, 1909) to the white-sided section of the genus andarranged as a full species, _Lepus altamirae_. In making this transfer, Nelson (_op. Cit. _:125) wrote that in "This well marked species . .. Thelack of a black patch on the posterior half of the ear at the tip andthe white flanks (somewhat obscured in some of the original specimens)are strong characters which place it in the _callotis_ group. ""Posterior half of ears white without any trace of black at tip", wasthe way Nelson (_op. Cit. _:124) described the ears in _L. Altamirae_. Myexamination of the original series including the type, reveals that theears do have some black at the tip of the posterior half in three of thespecimens, some brown in one other specimen, and only a dusky tinge intwo others. In the four specimens of _L. C. Curti_ the tip of the ear isfaintly brownish in one animal and dusky in three. The extent of thewhite flanks seems to be identical in the two series. Fortunately theyare in the same pelage and same stage of molt on the hind legs. The onedifference that I can detect is in the coloration of the nape. In eachof the specimens of _L. Altamirae_ the coloration is as described byNelson (_op. Cit. _:124): "nape with two lateral black bands extendingback from base of ears, and separated by a median band of buffy. " In _L. C. Curti_ the nape is all black in one specimen and the median band ofbuffy is present in the other three but is narrower and more dusky thanin _L. Altamirae_. Since the characters (color of tip of ear and extentof white on the flank) relied upon by Nelson for placing _L. Altamirae_in the _callotis_ group are duplicated in the _californicus_ group, in_L. C. Curti_, there is reason for questioning whether _altamirae_ iscorrectly placed, taxonomically, in the _L. Callotis_ group. Cursory examination of skulls of the _callotis_ group and the_californicus_ group indicates that the prepalatal spine (the part ofthe palate which extends anteriorly toward the vomer) is longer in _L. Californicus_ than in _L. Callotis_, _L. Gaillardi_ and _L. Alleni_. Inthis feature, _L. Altamirae_ agrees with _Lepus californicus_ anddiffers from members of the _Lepus callotis_ group. Furthermore, thenewly named _L. C. Curti_, in color of ear and color of nape, isintermediate between _L. Altamirae_ and _L. C. Merriami_. Consequently, _Lepus merriami altamirae_ Nelson, it seems, should stand as _Lepuscalifornicus altamirae_. Mention should be made here of the view of Shamel (Proc. Biol. Soc. Washington, 55:25-26, May 12, 1942) that the _californicus_ group shouldbe divided into two groups (each group possibly amounting to somethingmore than a species and something less than a subgenus) on the basis ofa white rump and complex infolding of the enamel layer of the front ofthe first upper incisor _versus_ a dark rump and simple infolding of thementioned layer of enamel. He placed _Lepus californicus merriami_Mearns, among other subspecies, in a group different from the one inwhich he placed several other subspecies of _Lepus californicus_. Specimens (skulls with accompanying skins) of the species _Lepuscalifornicus_ in the Biological Surveys Collection of the United StatesNational Museum, representative of a gradual transition from the darkrump and simple fold in the enamel to the white rump and complex fold inthe enamel are as follows: _L. C. Deserticola_, No. 29733/41808, Paharanagat Valley, Nevada; Nos. 117463 and 156744, Beals Spring, Arizona. _L. C. Texianus_, No. 24635/32031, Springerville, Arizona; No. 97453, Roswell, New Mexico; No. 118751, Toyah, Texas; No. 118749, Valentine, Texas; and No. 108700, Terlingua Creek, Texas. In thecontinuously distributed species _Lepus californicus_, along thenorthwest to southeast line provided by the localities of occurrencelisted immediately above, there is a gradual transition from one kind offold to the other kind and from one color of rump to the other color. It is clear that Shamel (_op. Cit. _) was in error in his conclusions;the kinds of black-tailed jack rabbits to which Shamel (_op. Cit. _)applied the name _Macrotolagus_ should stand as given below. Correct names: _Lepus alleni alleni_ Mearns _Lepus alleni palitans_ Bangs _Lepus alleni tiburonensis_ Townsend _Lepus gaillardi gaillardi_ Mearns _Lepus gaillardi battyi_ J. A. Allen _Lepus callotis_ Wagler _Lepus flavigularis_ Wagner _Lepus californicus altamirae_ Nelson _Lepus californicus melanotis_ Mearns _Lepus californicus merriami_ Mearns _Lepus californicus asellus_ Miller _Lepus californicus festinus_ Nelson _Lepus californicus texianus_ Waterhouse MEASUREMENTS (IN MILLIMETERS) OF ADULTS OF TWO SUBSPECIES OF LEPUSCALIFORNICUS Key: A Total length G Breadth of rostrum above premolars B Tail-vertebrae H Depth of rostrum in front of premolars C Hind foot I Interorbital breadth D Ear from notch in dried skin J Parietal breadth E Basilar length K Diameter of bulla F Length of nasals-------------------------------------------------------------------------- _L. C. Curti_, type locality (K. U. ) A B C D E F G H I J K[Female] 35470 565 55 125 115 72. 0 37. 1 25. 9 21. 2 27. 4 29. 8 13. 5[Female] 35471 566 57 122 122 72. 8 39. 0 25. 5 22. 0 26. 2 29. 2 13. 9[Female] 35472 520 50 115 105 69. 5 38. 6 26. 0 19. 0 24. 4 30. 2 13. 5[Female] 35473 587 53 124 118 72. 0 40. 9 26. 7 22. 2 27. 4 29. 0 13. 0Average 560 54 122 115 71. 6 38. 9 26. 0 21. 1 26. 4 29. 6 13. 5--------------------------------------------------------------------------_L. C. Altamirae_, type locality (U. S. N. M. , Biol. Surv. Coll. ) A B C D E F G H I J K[Male] 93691 605 96 137 112 76. 5 44. 5 26. 6 24. 6 . .. . 32. 0 13. 0[Female] 93692 595 71 137 114 77. 1 42. 5 26. 3 23. 1 27. 0 29. 5 13. 4[Male] 93693 590 93 137 110 77. 8 43. 8 27. 6 22. 5 27. 2 30. 7 14. 2[Female] 93694 605 70 142 118 78. 0 45. 9 26. 8 23. 4 28. 7 32. 0 14. 3[Male] 92982 556 59 136 114 75. 9 46. 5 26. 1 22. 3 25. 8 . .. . 14. 0Average 590 78 138 114 77. 1 44. 6 26. 7 23. 2 27. 2 31. 1 13. 8-------------------------------------------------------------------------- 1. In each specimen of _L. C. Curti_ the length of the ear measured from the notch when the animal was in the flesh was eight millimeters more than in the dried skin. The cranial measurements given above are taken, in so far as possible, in the same way that the measurements recorded by Nelson in his NorthAmerican Fauna (No. 29, 1909) were taken. In that publication he recordsmostly average measurements but he records also some measurements ofindividual specimens. Two of these specimens are the holotypes of_Sylvilagus mansuetus_ Nelson and Romerolagus nelsoni Merriam. Byattempting to duplicate Nelson's measurements on these specimens, thefollowing opinions were formed. "Basilar length" is basilar length of Hensel and the anterior point probably was the posterior border of the alveolus of incisor two. There is some evidence of lack of consistency with respect to the anterior control point. "Length of nasals" is the overall length, of the two nasal bones, but in _Romerolagus_ the shorter (right) nasal alone seems to have been measured. "Breadth of rostrum above premolars" is easily duplicated in _Lepus_ but in _Sylvilagus_ the control points are difficult to find. Two other persons and I obtained three different measurements, all different from Nelson's measurements, and we thought that Nelson would have obtained different measurements by measuring the same specimen of _Sylvilagus_ at different times. "Depth of rostrum in front of premolars" seems to have been taken perpendicular to the inferior longitudinal line of the rostrum, approximately one-half millimeter anterior to the alveolus of the anteriormost cheek tooth. "Interorbital breadth" was taken across the supraorbital processes, at the narrowest place, but _not_ from the notches medial to the antorbital projections of the supraorbital processes. "Parietal breadth" is the breadth, across the braincase, taken approximately half way between the squamosal root of the zygoma and the external auditory meatus, where there is a lateral bulge in the squamosal bone. On each side of the skull, the calipers rest on the squamosal bone, not on the parietal bone. "Diameter of bullae" excludes the paroccipital process and was taken from the anteriormost part of a tympanic bulla, posterolaterally to the part of that same bulla, that is exposed at the lateral side of the base of the paroccipital process. _Specimens examined. _--Total, four, all from Tamaulipas, Mexico, asfollows: 88 mi. S and 10 mi. W Matamoros, 3; 90 mi. S and 10 mi. WMatamoros, 1. _Transmitted February 20, 1951. _ 23-7414