96. ARRHTTON. 251 



Snout shorter than in L. torquatus ; upper portion of rostral as 

 long as its distance from the frontal ; praefrontal separated from the 

 eye by a small praeocular. Scales in 17 rows. Ventrals 191 ; sub- 

 caudals 93. Uniform grey-brown above, yellowish white beneath. 



Total length 346 millim. ; tail 105. 



Isthmus of Tehuantepec. 



3. Leptocalamus sclateri. (PLATE XII. fig. 1.) 



Rostral smaller than in L. torquatus, nearly twice as broad as 

 deep, the portion visible from above measuring about one third its 

 distance from the frontal ; internasals shorter than the praefrontals, 

 which largely enter the eyes ; frontal large, kite-shaped, slightly 

 longer than broad, much longer than its distance from the end of 

 the snout, as long as the parietals ; supraocular very small ; loreal 

 longer than the nasals ; no praeocular ; two postoculars ; temporals 

 1 + 2 ; seven upper labials, third and fourth entering the eye; five 

 small equal chin-shields, the anterior a pair in contact with three 

 labials. Scales in 15 rows. Ventrals 144 ; anal divided ; sub- 

 caudals 98. Uniform dark brown above ; head yellow, with a black 

 blotch on the snout and another round each eye ; lower parts uni- 

 form yellowish. 



Total length 380 millim. ; tail 150. 



6. America. 



a. $ (V. 144 ; C. 98). S. America. P. L. Sclater, Esq [P.]. 



96. ARRHYTON. 



Arrhyton, Gunth. Cat. Col. Sn. p. 244 (1858). 



Cryptodacus, Gundl. $ Peters, Mm. Berl. Ac. 1861, p. 1002 ; Bocourt, 



Misg. Sc. Me.r., Sept. p. 560 (1883). 

 Colorhogia, Cope, Proc. Ac. Philad. 1862, p. 81. 



Maxillary bone short, with 8 small teeth, followed, after a con- 

 siderable interspace, by a strongly enlarged fang; palatine and 

 pterygoid teeth few ; mandibular teeth small, equal. Head slightly 

 distinct from neck ; eye rather small, with round pupil ; nasal 

 entire or semidivided. Body cylindrical, moderately elongate ; scales 

 smooth, without apical pits, in 15 or 17 rows ; ventrals rounded. 

 Tail moderate ; subcaudals in two rows. 



Cuba. 



Synopsis of the Species. 



Nasal semidivided ; praefrontals distinct, in 



contact with labials 1. Urniatum, p. 252. 



Nasal entire; praefrontals and loreal distinct. 2. vittatum, p. 252. 

 Nasal entire ; prsefrontals coalesced ; loreal 



distinct 3. redimitum, p. 252. 



