ZOOLOGY-REPTILES. 
7 
Dimensions. —Length of head, neck, and body, 4| inches ; greatest breadth of head, 1 inch ; 
length, 1 inch ; tail mutilated, circumference at base If inch ; length of anterior extremities, If 
inch ; of foot to extremity of longest toe, f inch ; of posterior extremity, 2-|- inches ; of foot, 
posteriorly, to extremity of longest toe, 1 inch. 
Habitat. —Same. 
DIPSOS AURUS, H a 11 o w e 11. 
Gen. Char. —Head triangular, small, covered above and in front with tubercles, those upon 
the front the largest ; gape of the mouth moderate, its posterior extremity on a line with the 
posterior margin of the orbit; eyelids covered with granulations, their edges with scales pre¬ 
senting a denticulated margin ; a row of narrow, oblique, imbricate scales over the orbit ; scales 
upon orbit polygonal, unequal, the four or five inner rows the largest; temples covered with 
smooth polygonal tubercles, of unequal size ; teeth tricuspid, closely set on the inner side of 
the jaw, the posterior largely developed ; no palatine teeth ; tongue arrow-shaped, slightly 
notched in front, deeply cleft posteriorly; nostrils latero-superior, opening in a single scale; 
rostral plate vertical, triangular ; jaws margined each with a series of smooth, quadrilateral 
plates ; tympanum visibly depressed ; anterior margin of auricular opening denticulated ; upper 
part of body covered with carinated scales, more or less rounded posteriorly, arranged in oblique 
rows ; a row of scales much larger than the rest, along the dorsal line and much more strongly 
carinated, forming a slight dorsal crest; a gular fold; scales of abdomen, quadrangular, smooth ; 
femoral pores, but no anal ones; tail long, cyclo-tetragonal at base, tapering gradually to a point, 
covered with transverse rows of verticillate and carinated scales. 
DIPSOS AURUS DORSALIS. 
Svn. — Crotajohytus dorsalis , Baird and Girard. Proceed. Acad. Nat. Sc. 1852, p. 126. 
Sp. Char. One hundred and nine scales may be counted in one of the transverse rows running 
round the body near its middle, and terminating at the larger dorsal row ; scales upon throat 
much smaller than those upon chin and abdomen ; scales upon upper part of anterior and 
posterior extremities carinated ; posterior surface of thighs granulated; the granulations sur¬ 
rounded with minute granules ; third and fourth finger of nearly equal length ; fourth toe 
much the longest; margins of fingers and toes denticulated, inferior surface presenting trans¬ 
verse rows of carinated scales ; posterior extremities much stouter than the anterior ; sides of 
neck folded. 
Coloration. —Body presenting numerous lines of red upon the sides, with blotches of the same 
color over the shoulders, the intervening spaces numerous white spots ; upper surface and sides 
of tail marked with red spots arranged in transverse rows ; upper surface of extremities with 
red ; throat, abdomen, under surface of extremities, and tail white. The coloration, as des¬ 
cribed by Professors Baird and Girard, appears to be taken from young specimens, one such 
before me corresponding with it precisely. 
Dimensions. —Length of head, I lines; breadth, 7; length of head, neck, and body, to vent, 
8 inches, (Fr. ;) of tail, 7J inches; anterior extremities, inch; posterior, 3 inches, to extremity 
of nail of longest toe. 
Habitat. —Desert of the Colorado, to which it appears to be confined. The smaller specimen 
