TEIID LIZATIDR OF THE GENUS CNEMIDOrTTOP.US 65 



Coziimel Island U.S.N.M. Nos. 4T653-4T655) : Body, 57-75 mm.: 

 tail, 137-141 ; total length, 194-216 ; width of head, 7-10 ; hind leg, 

 42-52; supraoculars 3-3 in one specimen, and 3—1: (fourth vestigial) 

 in two specimens; supraocular granules extendnig forward to the 

 middle of the third supraocular in two specimens, and to the anterior 

 border of the third supraocular in one specimen. The frontoparietals 

 of these three specimens are all abnormally divided and in different 

 wa3's ; the result is three scutes in every case. 



A single specimen from Mujeres Island (U.S.N.M. No. 47652) 

 is typical in coloration and in other features as Avell. It is 64 mm. 

 long and has a regenerated tail ; the head width is 7 mm. ; and the 

 hind leg is 44 mm. long. Some other features are : supraoculars, 3-3 ; 

 supraocular granules extending forward to the middle of the third 

 supraocular; and femoral pores 17-18. The frontoparietal is partly 

 united from behind, but there is a squarish lateral scute split off 

 from each external border posteriori}^ to produce a total of three 

 scutes. This arrangement is often found in the South American 

 teiid, Dicrodon lentiginosus. 



In the original description Gadow, using an underline, emphasized 

 the fact that " not only the first but also the second and even the 

 third upper labials are denticulated." This seems to be a very unim- 

 portant distinction, however, since the same condition is found fre- 

 quently in depy'u. 



In all of the specimens examined by the writer the loreal is in 

 contact with the first supraoculai', but the amount of contact varies 

 considerably, and like the denticulation of the upper labials, it is not 

 wholly diagnostic. 



Range. — Specimens of this lizard have been examined from two 

 islands which lie off the east coast of Quintana Roo, Peninsula of 

 Yucatan, in southern Mexico. These are: {Gozumel Island., Gadow, 

 1906, p. 316, U.S.N.M.; and Mujeres Island, U.S.N.M.). 



A-ffinitles. — This form is structurally identical with depjyli, from 

 which it differs only in coloration. Specimens from the mainland 

 {deppii) sometimes possess a more or less widened middorsal yellow- 

 ish streak which resembles that of sexlineatus. In these the lateral 

 stripes are usually straight, but occasionally they are more or less 

 wavy. The transition from these to cozumelus is but a step. This 

 is accomplished by the widening of the dorsal band and the modifica- 

 tion of the lateral stripes. Thus, cozumelus may l)e considered as a 

 direct derivative of the wide-ranging mainland deppii., from which 

 it has probably been diff'ei'cntiated for a comparatively short time. 

 (For a comparison of the tyi)ical color patterns of the two lizards see 

 figure 14.) 



