TEIID LIZARDS OF THE GENUS CNEMIDOPHORUS 2U7 



tudinai airaiigeinent in the iloisal markings, but a clotie exaiiiiiia- 

 tion sometimes shows a continuous light brown area or a chain of 

 black spots extending longitudinallj' for some distance. In no case 

 is this developed enough to even ai)pr()arh the condition found nor- 

 mally in tesseUatus. The entire under surface is blackish in color, 

 the gular region often having numerous small light spots, and white 

 flecks may sometimes appear on the breast, or even on the posterior 

 part of the body, the under surface of the limbs or at the base of the 

 tail. As in the phase of tesseUatus^ described by Cope as melanos- 

 tethus^ the black is usually in greater intensity on the breast. The 

 femoral jDores are usually very hard to count because of the black- 

 ish suffusion which covers the lower surfaces of the hind legs. 



Fourteen specimens, including the type and paratype of this 

 subspecies, have been examined, and data taken from them may be 

 summarized as follows: Body, 38-76 mm.; tail, 91-179; total length, 

 129-250; length of tail as percentage of total length, 70.5-73.0; width 

 of head, 5.5-10.0; width of head as percentage of body length, 

 12.5-15.8; hind leg, 26.5-47.0; length of hing leg as percentage of 

 body length, 5-1.0-68.3; supraoculars four in 12 specimens, five in 

 2 specimens; supraocular granules extending forward to the ante- 

 rior border of the fourth supraocular in one specimen, to the middle 

 of the third supraocular in 11 specimens, and to the anterior border 

 of the third supraocular in 2 specimens. 



Range. — The typical form is confined to the small mass of land 

 in the Gulf of California, Mexico, that is called San Pedro Marti/- 

 Island (Stejneger, 1891, p. 407, U.S.N.M., C.A.S.) ; but, inter- 

 grades with canus are found on South San Lorenzo Island (Van 

 Denburgh, 1922, p. 541, C.A.S.) , to the northward. 



Habitat and hahits. — The available information on this subject 

 is apparently confined to the following brief statement by Van Den- 

 burgh (1922) : "■ These rather rare lizards were found along the 

 rocky slopes of the island. Their very dark coloration caused them 

 to show plainly against the snow white rocks over which they were 

 running.'' 



A-ffinities. — Cope (1900, p. 584) noted the close relationship of this 

 form with '" melanostetlnisll'' the variant of tesxeUatus with much 

 black inferiorly, from which he supposed it to differ ""in the exten- 

 sion of the black over the entire ventral surface." Examination of 

 additional specimens has shown that this distinction is valueless, 

 since numy tesseUatus specimens have as much black ventrally as 

 examples of rnartyrls. However, as shown in the diagnosis, there 

 are certain distinctive differences which se])arate the two forms. 



Martyr'ts and its small allies, canus, haeatus^ and cataliiiensis^ 

 represent an end development in the evolution of the color pattei-n 



