On a new Genus of Snakes from Brazil. 31 



longer than broad, with posterior processes truncate. Humeral 

 process granulate, not keeled, little longer than broad, obtusely 

 pointed, extending nearly as far back as occipito-nuchal 

 process. Skiu vviihout villosities. Dorsal I 7; spine as 

 long as head, feebly curved, striated, serrated beiiiiid. Adi- 

 pose dorsal as long as or a little shorter than its distance 

 from rayed dorsal. Anal IV 7. Pectoral spine strongly 

 serrated on both sides. Caudal fin deeply notched, crescentic. 

 Caudal peduncle about as long as deep. Pale brown above, 

 white beneatii ; head with numerous small round dark brown 

 spots ; body with large round dark brown spots, the ground- 

 colour between them forming a light network ; fins white, 

 with more or less regular black bands, 5 to 7 across dorsal, 3 

 or 4 across ventral and anal, 7 to 11 on caudal. 



Total length 200 mm. 



Mr. G. L. Bates obtained several specimens of this hand- 

 some fish at a waterfall of the Libi Kiver, near the Ja River 

 (Congo System), into which it flows. 



IV. — On a new Genus of Snakes from Brazil. 

 By G. A. BOULENGER, F.R.S. 



Among some snakes from Brazil, submitted to me for identi- 

 fication by Dr. Vital Brazil, Director of the Serumtherapic 

 Institute of S. Paulo, I was highly pleased to find a large 

 specimen which represents a species which has hitherto 

 escaped attention. In its physiognomy, head-shields, vertical 

 pupil, and dentition it agrees with tlie genus Oxyrhopus, 

 differii-g, however, in the scaling of the body, the scales 

 being in 25 rows, those of the vertebral row distinctly 

 enlarged. After some hesitation, I have decided not to place 

 the snake in the genus OxyrhopuSj but to propose for it a 

 new genus, which may be called Rhachidelus, 



Rhachidelus hraaili. 



Eye moderately large, its diameter equal to its distance 

 from the oral border and 5 the length of the snout, which is 

 rounded, rather strongly depressed, and scarcely projecting. 

 Rostral once and two-thirds as broad as deep, the portion 

 visible from above measuring one-third its distance from the 

 frontal; internasals nearly as long as broad, two-thirds the 

 length of the prsefrontals ; frontal pentagonal, as long as 



