388 FISHES. 



teeth. 15 feet long; beak nearly a third of the total length. In- 

 habits European seas. Sharv, v. 357- 



P. pectinatus, Lath. Beak armed with thirty-four sharp teeth on 

 each side ; tail longer than the preceding. Inhabits European 

 seas. Lin. Trans, ii. pi. 26. fig. 2. 



P. cuspidatus, Lath. Beak armed with twenty-eight teeth on each 

 side, of nearly equal breadth throughout. Inhabits European seas. 

 Lin. Trans, ii. pi. 26. fig. 3. 



FAMILY II. PLATYSOMI. 



Body much flattened, discoidal, with the eyes and spiracles on 

 the back ; nostrils, mouth, and branchial openings below ; 

 sides bordered by large pectorals. 



The body in this family is much flattened horizontally and resembles a disc, from 

 its union with the extremely large and fleshy pectoral fins. These fins, which are 

 joined to one another before or to the snout, extend backwards on both sides of the 

 abdomen to the base of the ventral fins. The scapulae of the pectoral fins are arti- 

 culated with the spine behind the branchiae. The dorsal fins are almost always on 

 the tail. The ova of this family are brown, coriaceous, and square, with pointed angles. 



Gen. 15. RHINOBATUS, Schn. Raia, Lin. 

 Five branchial openings on each side below ; snout angular ; 

 body flat ; tail long and very thick at the base ; dorsal and 

 caudal fins distinct ; teeth serrated, and in quincunx order. 



K. vulgaris, Cuv. Body elongated, brown above, paler below, with 

 one row of dorsal spines ; first dorsal fin behind the ventral ones. 

 4 feet long. Inhabits European seas. Shaw, v. pi. 147. 



R. Djiddensis, Forsk. Body pale cinereous, with three rows of 

 spines on the anterior part of the back ; first dorsal fin above the 

 ventral ones. Inhabits the Red Sea. Shaw, v. 319. 

 The genus RHINA of Schneider differs not from the present, otherwise than in 



the type of it, R. ancyclostomus, having the snout short, broad, and rounded. 



Gen. 16. TORPEDO, Dum. Raia, Lin. 



Body smooth, depressed, obtuse before, and nearly circular ; an- 

 terior border formed by productions of the snout, which ex- 

 tend along the sides to meet the pectoral fins ; five branchial 

 openings on each side, beneath ; electrical organs on the 

 sides ; teeth small and pointed ; tail short and fleshy. 



This singular tribe of fishes, and their electrical powers, was well known to the an- 

 cients. Oppian relates, that when taken by a hook and line they benumb the astonish- 

 ed fisherman; and Pliny affirms, that, when touched by a spear or stick, the paralyz- 

 ing effect is communicated in a high degree. The observations of Redi and others 

 in the 17th century tended in some degree to make known the peculiar action and ana- 

 tomy of the Torpedo ; and later investigations have elucidated the singular faculty it 

 possesses. The electrical apparatus, contained in the space between the pectoral fins 

 and the head and branchiae, is formed of small united membranous tubes, subdivided by 

 horizontal diaphragms and minute cells filled with a mucous substance. These are 

 abundantly provided with nerves, which come from the eighth pair. In this appara- 

 tus resides the electric power which has rendered the fishes of this genus so celebrat- 

 ed, and which perhaps is given them for the purpose of stunning their prey. 



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