in the Collection of the British Museum. 481 



Anacyrtus affinis. 

 D. 11. A. 55. L. lat. 80. 



Upper and lower jaws on each side with a pair of short, 

 conical, tooth-like processes directed forwards and outwards. 

 Intermaxillary teeth in two irregular series, — those of the man- 

 dible being in a single series, two pairs of them larger than 

 the rest, canine-like. Maxillary with four or five distant, 

 short, conical teeth. Back much elevated, the profile on the 

 nape being deeply concave. The height of the body is con- 

 tained twice and two-thirds in the total length (without 

 caudal), the length of the head four times. 



Lower jaw considerably shorter than the upper ; maxillary 

 not extending to the vertical from the front margin of the eye. 

 Suborbital touching the lower prseopercular limb. The dia- 

 meter of the eye is equal to the width of the interorbital space, 

 or to the length of the snout, and two-sevenths of that of the 

 head. Origin of the dorsal fin opposite to that of the anal, 

 rather nearer to the end of the snout than to the root of the 

 caudal. Pectoral extending beyond the vent. 



Huallaga. 



Anaci/rtus {Cynopotamus) amazonuin. 

 D. 11. A. 40. V. 8-9. L. lat. 110. 



The height of the body is contained twice and two-thirds 

 in the total length (without caudal), the length of the head 

 thrice and three-fourths. Upper profile deeply concave on 

 the nape, the back being much elevated. Abdomen not com- 

 pressed, but with a median ridge from behind the ventrals. 

 The intermaxillary and mandibulary teeth are in a single 

 series. The upper jaw overlaps the lower slightly ; the max- 

 illary extending far behind the eye, which is rather small, 

 placed in the middle of the depth of the head, nearer to the 

 snout than to the gill-opening. Suborbital slightly and ir- 

 regularly striated. Origin of the dorsal fin nearer to the end 

 of the snout than to the root of the caudal, its last ray being 

 opposite to the origin of the anal fin. Operculum very 

 narrow ; a naked space between the suborbital and lower 

 limb of the opercle. 



Xeberos. 



Sternopygus axillaris. 



Orbit without free eyelid ; mouth of moderate width, with 

 the jaws even in front ; upper profile of head and nape nearly 

 straight. A large blackish spot on the beginning of the 

 lateral line. 



Para. 



