170 



NORTH AMERICAN FAUNA. 



[No. 7. 



dotraphytus silus Stejn. 



Nine additional specimens from the San Joaquin Valley confirm the 

 distinctness of this species. 



In addition to the very strongly marked proportional differences in 

 the head pointed out in the original description (1ST. Am. Fauna, No. 3, 

 p. 105,) it is now found that the coloration is also essentially different. 

 In G. silus the rounded dorsal spots are larger, especially the two 

 median rows, so that of the latter there is only one longitudinal series 

 between the light cross-bauds. The latter are very broad and distinct 

 and do not seem, to disappear as the animal grows larger. In some 

 specimens the interspaces between the light bands are solidly dark, 

 the spots indicated only by somewhat ill-defined patches of saturated 

 ferrugineous. 



This species seems to be closely restricted to the San Joaquin Val- 

 ley, while the typical G. wislizenii reaches the west slope of the Sierra 

 Nevada through Walker Pass, the summit of which is only 5,100 feet 

 in altitude and, therefore, not above the vertical range of the species. 

 This fact is demonstrated by two specimens brought home by the 

 expedition, viz, No. 18298 which was collected by Mr. Palmer at Kern- 

 ville, June 23, and No. 18297 collected by Dr. Merriam at Havilah, June 

 24. Kernville and Havilah are on the west slope of the Sierra, and the 

 specimens from both are undoubted G. wislizenii both as to proportions 

 and coloration. If we were ever to find intermediate forms between the 

 two species, specimens from these localities would be expected to fur- 

 nish them, but it is a significant fact that they are as typical as any of 

 the specimens collected outside of the great interior valley of California. 



List of specimens of Crotaphytus silus. 



U.S. 

 Nat. 

 Mus. 

 No. 



18310 

 18311 

 18312 

 18313 

 18314 

 18315 

 18316 

 18317 

 18318 



Sex 

 and 



d 



d 



9 i uv - 



d juv. 



9 JUT. 



9 juv. 



9 



Locality. 



Alti- 

 tude. 



Tejou Ranch, Calif 



5 miles north of Rose Station. Calif. -.1 



do J 



l'oso, Calif I 



Bakersfield, Calif I 



do I 



do I 



do I 



Pampa, Calif I 



Feet. 



Date. 



July 13 

 Oct. 13 

 ..do .... 

 Oct. 10 

 July 17 

 Oct, 11 

 ...do... 

 ...do ... 

 July 16 



Collector. 



Palmer 

 Nelson . 

 ...do .. 

 ...do .. 

 Bailey . 

 Nelson . 

 ...do .. 

 ...do.. 

 Bailey . 



Remarks. 



Callisaurus ventralis (Hallow.). 



The large series of this interesting species brought home by the ex- 

 pedition has not only filled up gaps in our knowledge of its distribu- 

 tion, but has also afforded enough material to decide beyond a doubt 

 the question as to the specific difference between the present form and 

 typical Gallisaurus draeonoides Blainv. The differences are numerous 

 and are found both in structure and coloration. Moreover, after an 

 examination of about 200 specimens I can affirm that the characters 



