16 Dr. A. Giinther on new Species of Snakes 



Catostoma chalyhceum (WagL). 



A variety of this species, from the elevated country of Costa 

 Rica near Cartago, has a series of large, subquadrangular, 

 white spots along each side of the body. Sometimes the spots 

 of both sides are confluent and form white cross bars. Ven- 

 trals 144. In specimens of a uniform black coloration, from 

 Mexico, I count 130 ventral shields. 



Opisthoteopis (g. n. Calamarid.). 



Body and tail moderately slender, posteriorly somewhat 

 compressed ; head rather narrow, not distinct from neck. A 

 pair of anterior frontals ; a single postfrontal, which is very 

 broad. Rostral rounded. Nostrils between two nasals, di- 

 rected upwards. One loreal ; one ante-, two postoculars. 

 Eye small. Scales smooth anteriorly, with faint keels towards 

 the middle of the body, and strongly keeled behind and on 

 the tail, in 17 rows. Anal and subcaudals double. Maxillary 

 teeth equal in length, densely set, none grooved. 



West Africa. 



Opisthotropis ater. PI. III. fig. B. 



The upward direction of the nostrils reminds us in some 

 measure of the Homalopsidce ; but the pholidosis is that of a 

 Calamaroid snake. Rostral broad and low ; anterior frontals 

 about as long as broad ; postfrontal thrice as broad as long, 

 with an obtuse angle in front, but with the fronto-vertical 

 suture straight. Vertical triangular, occupying nearly the 

 entire width of the upper surface of the head, as broad as 

 long. Occipitals nearly twice as long as broad, obtusely 

 rounded behind. The nostril is small, in the upper part of 

 the suture between the two nasals ; loreal large, subquadran- 

 gular. The prteorbital reaches to the upper surface of the 

 head, but not to the vertical ; the upper postocular larger than 

 the lower. Seven labials, the fifth of which only enters the 

 orbit ; the seventh very long, as long as the single temporal 

 shield above it. Ventrals 170 ; subcaudals (j5. Upper parts 

 brownish black, lighter towards and on the abdomen. Length 

 of the head 3 inch, of trunk 10 inches, of tail 3 inches. 



West Africa. 



Leptocalamus (g. n. Calamarid.). 



Body and tail slender, subcylindrical ; head narrow, not 

 distinct from neck. Two pairs of frontals. Rostral rounded. 

 Nostrils small, between two nasals. Loreal united with prse- 

 ocular; two postoculars. Eye small. Scales smooth, in 17 



