TEIID LIZAEDS OF THE GENUS CNEMIDOPHORUS 153 



tif/ris, will be discussed here, but the fourth, graJtamii, will be con- 

 sidered Liter with stejncgeH. 



The Texas form, marmoratus^ was separated from tigrh by the 

 following features: "Smaller scales on back; larger scales on head 

 and belly; broader head on vertex; difference in shape of cephalic 

 plates; greater develo})ment of hind legs; and greenish ground 

 color." With the accumulation of additional material it became 

 eAddent that the diagnostic characters advanced were all due to either 

 age or individual variation, and consequently marmoratus was early 

 reduced to synonymy. The type specimen is in fairly good con- 

 dition. There are a few black spots on the sides of the head and 

 on the tlu-oat, and this is coutiuucd as a black mo'tliug on the chest 

 and abdomen. All of the doi'sal lines are broken and irregular and 

 the tessellation of the sides is c(>m})lete. A co-type has the same 

 coloration. Fi'om this descri])ti()n it is evident that mdvinoratus 

 represents a transition from the typical dull colored, browu-backed 

 specimens of the desert levels of the Great liasiu to the dark- 

 mottled form of the rougher, less sandy districts, which reaches its 

 end developuieut in what has been described froui Texas as (jvahamil 

 and from the west coast as stcpiegcrl. The undulatus of Hallowell, 

 which because of })reoccupati()n became the imindns of Camp, is the 

 Californian representative of this particular color phrase. These 

 statements are to be taken only in a general way, however, because 

 almost everywhere that tcssdlatus ascends to higher levels, even in 

 the Great Basin itself, transition toward the grahamii-stepiegeri 

 phase is seen. 



The type of gracilis was said to differ from ferplexus (which is 

 here considered as only a distant relative) in the narrower head; 

 in the proportionately longer body, tail and legs ; and in the smaller 

 scales on the lower surface of the head and throat. With our in- 

 creased knowledge of the variation exhibited by tesselJatus and 

 perplexus, it is very doubtful if any part of this diagnosis w^ould 

 hold to-day. The type is a young desert specimen with a slaty 

 throat and with considerable blackish suffusion below, and is indis- 

 tinguishable from the young of wdiat has been called " melanos- 

 tethus " by Cope. There are traces of six stripes on the body, 

 instead of four as stated in the original description, but those on 

 the sides are becoming broken into tessellations, Avhile those on the 

 back are only slightly irregular. Like marmoratus^ this form is 

 indistinguishable from tesselkitus. 



The Utah species, tigrh, was described as follows: "Scales on 



the subguttural (posterior gular) fold small in size; four yellowish 



indistinct stripes along the dorsal region." The former character 



is diagnostic of most of the specimens of the entire tesselJatus group, 



23(x;— 31 11 



