240 BULLETIN 15 4, UNITED STATES NATIONAL MUSEUM 



Two specimens have been collected by the writer at Janiul, near 

 San Diego, Calif., where they were found on a hillside which was 

 covered with moderate brush, grass, and cactus. In this habitat 

 there were numerous open spaces where the adobe soil was exposed 

 and not infrequently rocks were seen. It was noted that the speci- 

 mens were definitely associated with brush, which serves as a pro- 

 tection, rather than with the rocks or open spaces. Also, their 

 quick, jerky movements were typically those of a species of 

 Cneinidoflioii'us. 



Eneiiiies. — ^According to Van Denburgh (1922, p. 508), Mr. Slevin 

 found a specimen of the giant whiptail lizard, G ncmldo plior-us maxi- 

 Qiius, under a j^ile of brush, holding in its mouth a Vertlcaria (this 

 species) whose skull had been crushed in its powerful jaws. Also 

 (p. 673) a specimen of the black whip snake, Masticophis flagellunh 

 2)iceus was taken in a brush pile just after it had caught a specimen 

 of liyperythTus. 



Affinities. — The western orange-throated race-runner is very closel}^ 

 related to its subspecies, danhehnae^ caerideus, and pictus. All of 

 these forms are suggested by the normal variations of hyj^ein/thrus 

 and the transition to each is but a step (see fig. 33). Further infor- 

 mation in regard to this may be obtained from the discussion given 

 in the summary of the Jiajperythi'us group (pp. 246-249). 



The problem of the derivation of hyperythrus from the existing 

 Cnemidophorus stocks, and through this of the derivation of the 

 entire hyperytJirus group, is not easy. The most probable parent 

 form seems to be G. sexlineatus perplexus^ which is found east of 

 the Colorado River in Arizona. A more detailed consideration of 

 this problem will be given in the general discussion at the end of 

 this work (pp. 251-260). 



CNEMmOPHORUS HYPERYTHRUS CAERULEUS (Dickerson) 



CARMEN ISLAND RACE RUNNER 



1919. Vertlcaria cacruica Dickekson, Bull. Amer. Mus. Nat. Hist., vol. 41, p. 

 472, (tyi}e locality, "Carmen Island, Gulf of California, Mexico"; type speci- 

 men,^" U.S.N.M. No. 64251, C. H. Townsend, collector). — Van Denburgh, 

 Occas. Pap. Calif. Acad. Sci., vol. 10, 1922, p. 573. — Schmidt, Bull. Amer. Mus. 

 Nat. Hist., vol. 46, 1922, p. 681.— Nexson, Mem. National Acad. Sci., vol. 21, 

 1922, p. 114. — Stejneger and Bakeour, Check List N. A. Amph. and Rcpt., 

 ed. 2, 1923, p. 68.— Burt, Proc. Biol. Soc. Wash., vol. 42, 1929, p. 154. 



Diagnosis. — The Carmen Island race-runner differs from G. 

 hypetythrus hyperythrus by the presence of a single middorsal line 

 which has the same intensity and width as the lateral stripes, at 



=" The type is well preserved, but has several mutilations. Flesh is exposed by an 

 injury just back of the shoulders, the tail is partly broken 22 mm. from its base, and 

 shot marks may be seen in the breast, mesoptychium, and giilar region. A vrntral 

 incision is in-cscnt aloni; tlie left side of the body. 



