SHARKS AND SKATES. 89 



or jji'ickly. The single known species of TJrogymnus ( JJ. asperissimus) oocurs in the 

 Indian Ocean. " The skin is frequently used for covering shields and the handles of 

 swords and other weapons, its rough surface offering a firm hold to the hand." The 

 Chinese also use the skin in some of their ornamental work ; they dye it with some 

 color, and then polish the surface, grinding off the asperities. The pattern thus pro- 

 duced is very handsome, the bony plates and intervening tissue producing a mottled 

 appearance. The genus Potcmiotrygon contains the fresh-water rays of tropical 

 America. The species of XIrolophus have the body more or less circular in outline; 

 one species, TI. torjjedinis, occurs sis far north as 'New Jersey, and two others are found 

 on the Pacific coast of the United States. They have the serrated spine at the base of 

 the tail well developed. 



The eagle-rays and sea-de\ils (MvLiOBATiDyE) have a verj' broad disc and a pecu- 

 liar development of the fins. The pectorals stop short of the snout, and then reap- 

 pear as ' cephalic fins ' at the extremity of the head. In some, these take on almost 

 the character of limbs, are flexible, and are said to be used in scooping up food from 

 the bottom, and transferring it to the mouth, which lies between and behind them. 

 All liave the teeth flat and pavement-like, without cusps or tubercles (exce2:)t in the 

 sea devils), forming a perfect mill for crushing shells and crabs. The species mostly 

 occur in troiiical and semi-tropical waters ; they bring forth their young alive. The 

 largest species belong to the genera Dicerobatis and 3fanta. " Some of them, if not 

 all, attain an enormous size. One mentioned by Risso, taken off Messina, weighed 

 1250 pounds. Several observers speak of having seen them in pairs, the male being 

 usually the smaller. Of a pair mentioned by Risso, the female was first taken, and the 

 male remained hovering about the boat for three days, and was afterwards found floating 

 dead on the surface. Still larger individuals, but of uncertain species, are mentioned 

 by Lacepede, who says that one taken at Barbadoes required seven yolk of oxen to 

 draw it. A sketch of another, which was said to be twenty feet long, was sent to 

 Lacepede ; and Sonnini speaks of one which appeared to him to be longer and wider than 

 the ship in which he was sailing. A fostus taken from the uterus of the mother captured 

 at Jamaica, and preserved in the British Museum, is five feet broad, and weighed 

 twenty pounds. The mother measured fifteen feet in «-idth, as well as in breadth, 

 and was between three and four feet thick. The cajoture of 'devil-fishes' of such 

 large size is attended with danger, as they not rarely attack and capsize the boat. 

 They are said to be espiecially dangerous when they accompany their young, of which 

 they bring forth one only at a time." 



In the waters of tropical America, in both Atlantic and Pacific, and ranging as far 

 north as North Carolina and San Diego, occurs the monstrous Manta birostra, 

 probably the same species as that mentioned above from Jamaica and Barbadoes. It 

 has been described under various names, some of which are indicative of its unenvi- 

 able reputation. Such are Diabolichthys and Vampyriis, while the generic name Man- 

 ta (a blanket) is a " name used at the pearl fisheries between Panama and Guayaquil, 

 to designate an enormous fish much dreaded by the divers, whom it is said to devour 

 after enveloping them in its vast wings." 



The species of Myliobatis, Stoasodon (=^tobaHs), and Bhinoptera are much 

 smaller than the sea-devils ; still, some reach a considerable size. Like them, they have 

 a long slender tail, like a whip-lash, but the teeth are much larger, and never tubercular. 

 Each of these genera are represented on our coasts. 



J. S. KlNGSLBT. 



