CALLIRHIXUS P A T A G X I E X S I S. 139 



Fig. 4, an upper view of the head. 

 Fig. 5, a lower view of the same. 

 Fig. 6, the vent and preanal scutella. 

 Fig. 7j the dorsal scales. 



GEXUS CALLIRHINUS, GIRARD. 



CHAR. GEX. Capite et corpore colubriformibus. Rostro subconico, ultra 

 maxiUam inferiorem protenso. Scuto verticis elongate, rostrali 

 convexo. Scutis nasalibus duobus ; nare in sutura sita. Scutw 

 loreis duobus, praeorbitali uno, postorbitalilius duobus ; labicdibus 

 tertio et quarto in orbitam product is. Squamis modicis, laevibus. 

 Scutella praeanali divisa. Scutellis subcaudalibus in seriem duplicem 

 ordinatis. 



GEN. CHAR. Head and body colubrine. Snout subconical, protruding 

 beyond the lower jaw. Vertex plate elongated. Rostral convex. 

 Two nasal plates, with nostril between them. Two loral plates. 

 One anteorbital and two postorbitals. Third and fourth upper 

 labials entering into the orbit. Scales moderate, smooth. Preanal 

 Bcutella divided. Subcaudal scutellae disposed upon a double series. 



PYX. C'altirhinus, GED. in Proc. Acad. Nat. Sci. Philad. August, 1857, p. 182. 



OBSERV. This genus is related to Rldnechis and PltuopJtls ; the 

 labial plates are less numerous than in the latter two genera, and so 

 also are the series of dorsal scales. The teeth are uniform and mo- 

 derately developed. The eye is large, and the pupil circular. The 

 preanal scutella is subdivided, as in Rhinechis. 



CALLIRHINUS PATAGOXIENSIS, Grd. 

 (Plate XII, figs. 1-6.) 



CHAR. SPEC. Squamis in novemdecim series lonyitudinales dispositis. 

 Colore olivaceo, rtigro-maculato. 



