DOLIOSATTRUS. 407 



by these spines being set closely together, so as to leave no interval 

 between them at their base. An approximation of a similar arrange- 

 ment of the cephalic spines may be observed in D. mccalli, in which, 

 however, the spines themselves are not contiguous. P. regale is the 

 only species which is provided with four subequal occipital spines. 



Loc. Valleys of the Zuni and Colorado Rivers. 



SUBGENUS DOLIOSAURUS, Grd. 



GEN. CHAR. Head rather small and abbreviated ; vertex very large, 

 slightly inclined forwards ; snout abruptly truncated. Nostrils an- 

 terior, situated within the extension of the supraciliary ridge. 

 Cephalic plates moderate, or small, rugose ; spines but moderately 

 developed ; occipitals higher than the temporal ones. Subrnaxillar 

 shields large, sharp-edged. Auricular apertures sometimes but par- 

 tially visible externally, else entirely hidden under the skin. Mental 

 scales small, subequal ; gular scales minute. A double or triple 

 series of subpyramidal scales at the periphery of the abdomen, or 

 else none at all. Abdominal scales subrhombic, smooth, or slightly 

 carinated. Ground color olivaceous, or yellowish, maculated above 

 with black ; beneath unicolor. 



SYN. Anota, HALLOW, in Proc. Acad. Nat. Sci. Philad. VI, 1852,182; &, in Sitgr. 

 Rep. Exped. Zuni and Color. Rivers, 1853, 127. 



OBSERV. This genus is more intimately related to Phrynosoma, 

 than to any other of its congeners, since the abdominal scales of some 

 of its species exhibit exiguous keels. The head, however, is smaller, 

 more abruptly truncated, with the nasal region rather depressed. The 

 cephalic spines are much less developed also, whilst the vertex is 

 broader and nearly horizontal. The lower labials are small and sub- 

 equal. 



The auricular apertures, subjected to a good deal of variations in 

 their external development, constitute in our opinion a general feature 

 of no minor importance. We can only regret that the name of Anota, 

 imposed by Dr. Hallowell, could not have been made available for the 

 genus as it now stands, since it points at that structure as developed 

 in one of the species only. Never did we feel more reluctant in coin- 



