Garman.] 206 [May 2, 



principal uses would seem to be as rudders, to change the direction of 

 the body in swimming, and in coupling. 



Knowing from experience the desirability of descriptions of indi- 

 viduals of forms rare and difficult to secure, I have ventured to 

 describe a couple of species from single specimens rather than hide 

 the knowledge of their existence for years, it may be, in the hope of 

 securing duplicates. For the description a zoologist will overlook 

 the risk taken, and the mere compiler, who would denounce a syno- 

 nym most loudly, is entitled to much less consideration. The de- 

 scriptions and notes are taken from specimens in the Museum of 

 Comparative Zoology at Cambridge. 



Sympterygia acuta sp. nov. 



Disk rhombic, longer than wide. Pectorals meeting in an acute 

 angle at the end of the snout, with lateral and posterior angles 

 rounded, bearing the indentation of the sinuous anterior margin 

 about midway. When expanded, the ventrals have their posterior 

 borders in the same lines as those of the pectorals ; their anterior 

 portions are separated by a shallow notch from the posterior, and the 

 outer and hinder angles are acute. Tail depressed, quite thin toward 

 the end, with a fold on each side, bearing two small rounded fins 

 near the extremity. The back and tail and anterior halves of the 

 pectorals are rough with small sharp scales, the points of which are 

 directed inward and backward. A row of spines with broad bases 

 and sharp hooked points extends from the shoulders along the mid- 

 dle of the back to the second dorsal. Ventral surface smooth. Eyes 

 and spiracles small, about equal in size. Nasal valves as in Raja. 

 Mouth arching forward. Teeth small, subquadrangular on the base, 

 sharp in the middle series, blunter to flat toward the angles of the 

 mouth, in forty-two series on the upper jaw and forty on the lower. 

 Color reddish brown, darker on the dorsum and tail; white below. 



Total length 13.5; length of disk, including ventrals 9; length of 

 anterior borders of pectorals 5.8; posterior borders 6; and distance 

 from the end of snout to mouth 2.7 inches. 



Distinguished from S. Bonapartii M. et H. by the greater length 

 of disk as compared with its width, the greater length of snout, the 

 shorter tail and the shape of the ventrals. In S. acuta the ventrals 

 are one-fourth longer from the anterior extremity of the base to the 

 posterior angle than from the same point to the lateral angle; the 

 longitudinal measurement is least in S. Bonapartii. 



Specimen secured by the Hassler Expedition at Buenos Ayres. 



