42 BULLETIN 15 4, LTNITED STATES NATIONAL MUSEUM 



dorsal ground color black, brown, gray, or slate; sides often with 

 small flecks or spots. 



A series of 42 specimens has been examined and the data may be 

 summarized as follows: Body, 56-96 mm.; tail, 126-221; total 

 length, 182-313; width of head, 7.0-16..5; hind leg, 35-62; supra- 

 ocular granules extending forward to the middle of the fourth 

 supraocular in 25 specimens, to the anterior border of the fourth 

 supraocular in 15 specimens, and to the middle of the third supra- 

 ocular in 2 specimens. 



Variation. — Considerable geographical variation in color is evident 

 in the populations of the various islands upon which nigricolor has 

 been taken. On Aves Island the dorsal ground color is gray or 

 l)lackisli gray, but eastward on Los Roques it is always black or 

 brownisli. Still further eastward on Blanquilla Island the tone is 

 again grayish, but with a little blue. This same variation is found 

 south of this point on Margarita Island. 



There is apparently no variation in bodily proportions or in the 

 number of femoral pores. Also, all but the keeling of the ventral 

 caudal scales seems to be relatively constant in regard to the scutel- 

 lation. The ventral caudals, although showing variation in respect 

 to the keeling, are usually smooth in the lizards on all of the islands 

 mentioned above, except those on Margarita Island. This island 

 lies near the mainland of South America, and hence closer to the 

 present range of lemnlscafu!^. Here the ventral caudals are notice- 

 ably keeled, but not as much as in the normal mainland specimens 

 of lemniscatus. The coloration, too, is intermediate, the spots on the 

 sides being larger than is usual in nigrioolor.^ but smaller than is 

 usual in lemniscatus. Therefore, the Margarita specimens (particu- 

 larily F.M.N.H. No. 2682, series) are considered as intermediates, 

 if not intergrades, between nigricolor and Icnmiscatus^ and the pop- 

 ulations, distinguished on slight variations only, are held to be in 

 subspecific relation to each other. 



A single, additional, median posterior frontoparietal is present in 

 one of the specimens examined (Mich. 49800). This abnormality 

 is also shown by the type specimen of ruatanus (lemniscatus). 



Range. — The black race runner is known only from islands off 

 the north coast of Venezuela. It occurs from the Aves Island east 

 to Blanquilla Island and intergrades with lemniscatus through the 

 population on Margarita Island, south of Blanquilla. 



The available records are as follows: 



DUTCH LEEWARD ISLANDS.— (A^-es Island, Meek, 1910, 

 p. 417, F.M.N.H. ; Los Roqites Islands, Peters, 1873, p. 76, F.M.N.H., 

 M.C.Z., Mich.) 



VENEZUELAN lSl^K'^T>S.— {BlanquUla Island, Meek, 1910. 

 p. 417, F.M.N.H.; Margarita Island, Meek, 1910, p. 417, F.M.N.H.) 



