MUSEUM OF COMPAKATIVE ZOOLOGY, 201 



about 34 rows, counting upward and forward obliquely from the origin of tlie 

 anal to the dorsal line. Lateral line apparently absent. 



Head considerably compressed, with rounded upper surface, its length con- 

 tained about six times in total body length ; its width contained 2^ times in its 

 length ; its greatest height equal to two thirds its length. Snout slightly longer 

 tban the horizontal diameter of the eye, and projecting beyond the tip of the 

 upper jaw a distance equal to the vertical diameter of the eye ; much dilated 

 and swollen, the anterior pair of nostrils being situated at the most salient 

 angles ; the snout in general form resembling that of a manatee, whence the 

 specific name. 



Mouth moderate ; its cleft extending to the vertical from the centre of the 

 orbit. Length of the upper jaw equal to twice the horizontal diameter of 

 the eye, and contained 2^ times in the length of the head. The posterior 

 portion of the maxilla is considerably exjianded. The maxilla is largely 

 included within a skinny sheath. When the mouth is closed, the lower jaw is 

 entirely included within the iipper. Maxilla toothless. Vomer and palatine 

 bands of teeth more than twice as broad as the bands in the intermaxillaries 

 and on the mandible. 



Eye elliptical in form. Its vertical diameter two thirds of its horizontal, 

 the latter being equal to the distance from the tip of the snout to the posterior 

 nostril, and contained 5^ times in the length of the head. The distance of the 

 eye from the dorsal outline is equal to half its horizontal diameter, and to one 

 fifth of the height of the head in a perpendicular through the centre of the eye. 

 Interorbital space rounded : its width equal to the horizontal diameter of the 

 eye. 



Dorsal fin inserted in the vertical above the insertiori of the pectoral, at a dis- 

 tance from the end of the snout equal to that of the insertion of the pectoral. 



Anal inserted under the 21st to 23d dorsal ray, and at a distance from the 

 snout about equal to one third the body length. The height of the dorsal and 

 anal fins is about equal to half the height of the body at the insertion of the 

 anal. Their bases extend almost to the insertion of the caudal. 



The caudal is composed of nine rays, the five medial ones almost equal in 

 length, though the tip of the tail is slightly rounded, about equal to the height 

 of the body midway between the branchial opening and the base of the tail. 



The ventrals are inserted almost under the middle of the operculum ; in 

 length about equal to half the length of the head. 



The pectorals are inserted under the origin of the dorsal, and at a distance 

 behind the branchial opening equal to two thirds the vertical diameter of the 

 eye. Their length is equal to the greatest height of the body. 



Color, grayish brown. Abdominal region black. 



Radial formula : D. 106 ; A. 86 ; C. 2 + 5 -f- 2 ; P. 18-20 ; V. f 



L. lat., ca. 175. 



