44. TRIMORPHODON 885 
Brown, Proc. Acad. Nat. Sci. Phila., 1901, p. 91; STEJNEGER, 
Proc. U. S. Nat. Mus., Vol. XXV, 1902, p. 157; Mocquarp, Miss. 
Sci. au Mexique, Pt. III, Rept., 1908, p. 909, pl. 74, fig. 1, 1a-b; 
Dirmars, Reptile Book, 1907, p. 389; Van Densurcu & SLeEvin, 
Proc. Cal. Acad. Sci., Ser. 4, Vol. 3, 1913, p. 423; STEJNEGER & 
Barsour, Check List N. Amer. Amph. Rept., 1917, p. 104; VAN 
DensurcuH & Stevin, Proc. Cal. Acad. Sci., Ser. 4, Vol. XI, 1921, 
pp- 52, 70; Netson, Mem. Nat. Acad. Sci., Vol. XVI, 1921, pp. 114, 
rss 
Description —Head very distinct from neck, the tem- 
poral regions being swollen. Snout rather short, rounded, 
somewhat projecting. Rostral plate large, broader than 
high, bounded behind by internasal, anterior nasal and first 
labial plates. Plates on top of head are a pair of internasals, 
a pair of prefrontals, a frontal, supraocular of each side, and 
a pair of rather short parictals. Two loreals placed one in 
front of the other. Often a small subloreal in the notch 
between the second and third supralabials, below the poster- 
ior loreal, and in front of the inferior preoculars. Preocu- 
lars three or two. Postoculars three. Temporals normally 
three followed by four, sometimes 2+3. Usually nine 
(rarely seven) superior labials, the sixth or seventh largest, 
the fourth and fifth reaching eye. About 12 (sometimes 10 
or 11) inferior labials, the first pair meeting on the median 
line. Genials in two pairs, the anterior much larger. Scales 
on body smooth, in 20, 21, 22, or 23 rows. Anal plate 
divided. Gastrosteges varying in number at least from 231 
to 236. Urosteges in two series of about 70 to 74. 
The ground color above is gray. The head is crossed 
by a more or less indistinct grayish band which involves the 
anterior part of the prefrontals. The posterior half of these 
plates and the anterior portion of the supraoculars are crossed 
by a brown band with very concave posterior border. This 
band is continued upon the inferior postocular and the sixth 
supralabial. A broad band begins on each side of the center 
