58. PHRYNONAX. 19 



Praeocular in contact with or narrowly 

 separated from the frontal ; eight or 

 nine upper labials 5. fasciatus, p. 21. 



II. Scales in 25 rows. 



Dorsal scales very strongly keeled .... 6. eutropis, p. 22. 

 Scales smooth, except the row next to 



the vertebral, which is feebly keeled . 7. clinjsohronchus, p. 22. 



1. Phrynonax sulphureus. 



Natrix sulphurea, Warjl. in Spix, Serp. Bras. p. 26, pi. ix. (1824). 

 Coluber pojcilostoma, Wind, Beitr. Nat. Bras. i. p. 250 (1825), and 



Abbild. (1831) ; Schleg. Fhys. Serp. ii. p. 153, pi. vi. tigs. 5 & G 



(1837). 

 Spilotes pcBcilostoma, Dum. ^ Bibr. vii. p. 221 (1854) ; Giinth. Cat. 



p. 100 (1858) ; Jan, Icon. Gen. 48, pi. v. tigs. 3 & 4 (1876). 



Rostral broader than deep, visible from above ; internasals as 

 long as or a little shorter than the prsefrontals ; frontal as long as 

 broad or slightly longer, as long as its distance from the rostral or 

 the end of the snout, shorter than the parietals ; loreal longer than 

 deep ; one praeocular, not reaching the frontal ; three postoculars ; 

 temporals 1 + 1 ; eight upper labials, fourth and fifth entering the 

 eye ; five lower labials in contact with the anterior chin-shields, 

 which are as long as or a little shorter than the posterior. Scales 

 in 21 rows, aU except the outer row strongly keeled. Ventrals 

 distinctly angulate, 20S-226 ; anal entire ; subcaudals 126-144. 

 Yellowish, olive, or brown above, with or without black spots or 

 irregular cross bars ; the keels of the scales black ; belly yellow or 

 olive, sometimes turning to black posteriorly. 



Total length 2700 millim. ; tail 720. 



Guianas, Brazil, North-eastern Peru, Ecuador. 



A. Labials without black margins ; tail olive or brown. 



a. cJ (Y. 214; C. 129). Cabaros, Upper Amazon. Mr. E. Bartlett 



[C.]. 



b. Hgr. (V. 217 ; C. 139). Movobamba, N.E. Peru. Mr. A.H.Roff[C.]. 



c. 2 (V. 216 ; C. 134). Guayaquil. Mr. Eraser [C.]. 



d. Yg. (V. 216; C. 136). S. America. Zoological Societ}'. 



e. Yg. (Y. 208; C. 140). S.America. Dr. Pye-Smith 



[P.]. 



B. Sutures between some of the labials black ; tail black. 



/. S (V. 217 ; C. 144). Demerara Falls. 



ff. cJ (V. 215; 0. 139). S. America. Zoological Society. 



h. Skidl. Brazil. 



c2 



