CROCODILIANS, LIZAKDS, AND SNAKES. 



577 



the black grouud, or cut it into sectious or spots by expanding in both 

 directions. In the former case the dark stripes become irregular or 

 undulate in outline. This is their usual condition on tlie anterior part of 

 the body. On the posterior part of the body the dark ground is usually 

 broken into spots. In the type specimen of the (J. tigris Baird and 

 Girard, the breaking up of the black intervals has not been completed, 

 although the specimen is of full size. In typical specimens this part 



Fig. 107. 



Cnemidophorus tessellatus tessellatus Say, fi. 



_1. 



Utali. 



Cat. N... 41i:!, U.S.N.M. 



of the body is marked by three longitudinal rows of transverse black 

 spots. The upper surface of the tail is generally marked with brown^ 

 spots, sometimes rather large, but in other specimens confined to the 

 keels of the scales. In some they are wanting. 



In the last modification the traces of stripes have almost or quite 

 disappeared. The upi)er pair are first to be interrupted by transverse 

 and oblique extensions of the irregularly shaped black spots, and the 

 inferior stripes are finally interrupted and lost in the same manner. 



NAT MI'S 08 37 



