PISCES. 65 



Note. Platyrliina M. and H. (Sp. Raja chinensis Lac), a genus allied 

 to Torpedo, diflfers in habit from Rhinobatus. Comp. Plate in Muelleu 

 and Henle, 



Pristis Lath, Body elongate, depressed anteriorly, covered 

 with small flat scales. Pectoral fins distant from head, not pro- 

 duced to the ventrals. Tail with two dorsal and a caudal fin. 

 Teetli small, crowded upon a plane. Head produced anteriorly into 

 a depressed ensiform process armed Avith teeth at the margin on 

 each side. 



Sp. Pristis antiquorum Lath., Squalus pristis L., Bloch Tchth. Tab. 120, 

 Cuv. R. Ani., ed. ill., Poiss. PI. 117, fig. 2; the saw-fish {serra marina or 

 serra pristis), irplaTi? ; the name of the animal is borrowed from the weapon 

 with which its head is armed ; it measures J of the length of the body, and 

 has on each side from 20 to 30 elongato-conical teeth. 



Compare Latham in Transact, of tlie Linn. Soc. 11. pp. 282 and foil, 

 (Pristis Perotteti, from the Senegal, would seem to be found in fresh-water 



only.) 



Family V. SelacJn'i (s, Squali). Branchial apertures at tlie 

 sides of neck. Eyelids distinct, with margin free. Cartilaginous belt 

 of pectoral fins imperfect, not conjoined with vertebral column above. 

 Pectoral fins not produced in front of head. Anal fin in many. 



The Sharks. — This group is somewhat less numerous in species 

 than the preceding, although about one hiuidred v.ve known; more 

 than a fourth part of that number Hve in the seas of our part 

 of the woi'kl. In general this group seems, like that of the I'ays, 

 and even in a greater degree, to belong to the eastern hemisphere of 

 the globe ; from the South American coasts, Brazil, and the West 

 Indies, there are only few species, perhaps only one-tenth of the 

 whole number. They all live in the sea, although one species of 

 Carcharias is found in the Ganges at a distance of sixty hours from 

 the sea. Of these fishes some are widely dispersed, as Spinax 

 acanthias {Sq. Acanthias L.), Mustelus vulgaris (Squalics Mustehis 

 L.), which occur in the Mediterranean, the Atlantic, at the Cape, 

 and even in the South Sea. In this family the largest fishes are 

 found; many are more than six feet, Selache maxim<f, (^Squalus 

 niaximics) may be more thaii thirty feet long. 



Squatina DuMER. Body depressed; head rotundate, with mouth 

 anterior, eyes small, situated on the upper part of head. Two tem- 

 poral foramina behind the eyes. Teeth acuminate, conical. Bran- 

 VOL, TI, 5 



