TEIID LIZA1JD8 OF THE GENUS CXEMIDOPHOrvUS 171 



have been found almost everywhere at the edi^es of the (ireat Basin 

 and even in the basin itself where there are mountains. Because 

 of the unifoi'inity of tlie clianiie in fe-'^seUafifs, the continuous range, 

 and the <reneral possession of tiie more fundamental (constant) 

 characters, upon Avhich a valid taxonomic appellation should alwaj^s 

 rest, stepiegeri and tcssclldfiis are here recognized as one. 



The whiptails on Cerros Island were described as C. fcsseflafus 

 multfscutafus h\ Cope (1892c', p. 38), who stated that the coloration 

 was of the tessellatits type, but that the black ground color was more 

 persistent. The tail was said to be black spotted below. Van Den- 

 burgh elevated the form to full specific rank in 189.") and continued 

 to recognize it as a distinct species in his later works. In 1922 he 

 wrote of it as follows: "I am unable to find the differences Avhich 

 Cope stated to exist between this lizard and other members of the 

 fe.s.sel/afus group. The nine specimens from Cerros at hand seem 

 to be more like sfejne</eri than like any other race, although they 

 sometimes have the ashy suffusion of the gular region seen in fesseUa- 

 ius. The large, well defined l)lack markings on the sides of the head 

 and neck and on the gular region are similar to those of sfe/negeri 

 The marking on the lower surface of the tail. hoAvever, is quite dif- 

 ferent. Each of the scales of the inferior central rows has a large 

 central black spot. Xo such regular or abundant spotting is seen 

 in this region in sfejnegeH. Twenty-three specimens from Xatividad 

 Island agree with those from Cerros, but the black markings on 

 the lower surface of the tail are not quite so regularly distributed, 

 and those on the gular regioji are larger and more fre((U(Mitly form 

 ci'oss-bars.*" An «'x;iniin;it i(in of tlu> material seen by ^'an Denburgh 

 shows that the coloration is lai'gely intermediate between that of the 

 desert and ui)land phases for the indications of both ai'e seen. The 

 ventral i)arts vai'v in color from white to slate, and the markings on 

 the throat vary from a total absence to a prominent reticulation or 

 cross-barring of the region. There is nothing unusual or diagnostic 

 in the dorsal coloration, except that it tends to be duller than that 

 of certain specimens on the adjacent mainland. 



Usually the supposedly diagnostic subcaudal spots are on most of 

 the scales, but at times they are faint or partly al)sent. The occur- 

 ence of these spots is very common in tesseJIatus, particularly from 

 the northern part of the great interior basin of the west. This fact 

 was noted by Cope as early as 1900, at which time he wrote as fol- 

 lows: "I took a specimen which differs in no respect from muJtiscu- 

 tatvs on the road between Keno and Pyramid Lake in western 

 Nevada."' In spite of Van Denburgh's elevation of iniiltiscutatus to 

 a full species. (Jadow (190('), ]>. 370) wrote that " 'J'liis lizai'd can 

 scarcely claim distinctive rank," and he added that ""a specimen ob- 



