22 SELACHII: RALZ. —V. 
21. TORPEDO Duwm6éril. 
30. T. occidentalis Storer. TorprepO. CRAMp-FISH. NuMB- 
FisH. Black, with obscure darker blotches; spiracles with entire 
edges. L. 3 to 5 feet. Cape Cod S.; not common. 
Famity XVI. DASYATIDAK. (THE Stinc-Rays.) 
Disk broad, the pectorals confluent anteriorly, forming tip of 
snout; tail, usually whip-like, sometimes short and stout, with or 
without fins, but never with two dorsals. ‘Tail usually armed with 
a sharp, retrorsely serrate spine above, near the base (this often 
duplicated and sometimes wanting): ventral fins entire. Skin 
smooth or variously rough, the adult roughest. Mouth small, with 
small teeth. Sexes similar. Genera 10, species 50, in most 
warm seas. The large spine or “sting ” on the tail in most species 
may inflict a dangerous wound. 
a. Tail slender, whip-like, without caudal fin, ae than the disk; ‘‘sting”’ 
on tailstrong. . : Be lan Tis DASYATIS, 22. 
aa. Tail very slender ann hort’ shaver ‘fun the very broad disk: sting 
minute or wanting... . . « .» « » «© « « J SSROPBA TEA ea. 
22. DASYATIS Rafinesque. (Zygon Adanson.) 
(Sauvs, shaggy or rough; Baris, skate.) 
a. Tail with a fold on its lower margin only, the upper edge rounded. 
31. D. centrurus (Mitchill). Common Stine-Ray. CLAm- 
CRACKER. STINGAREE. Snout not prominent; disk a little wider 
than long; tail usually not quite twice length of disk. Adult 
with some stellate tubercles on back and tail. Color olive-brown. 
L. 12 feet. Cape Cod S., common. (xévrpov, spine; ovpd, tail.) 
aa. Tail with a fold of skin on its upper as well as lower margin. 
32. D. say (Le Sueur). SovuTHERN Stinc-Ray. Wurp- 
PAREE. Snout not prominent; disk a little wider than long; tail 
nearly twice leneth of disk. Body and tail without large spines. 
N. x, S. (To Thomas Say, a distinguished zodlogist.) 
23. PTEROPLATEA, Miiller & Henle. 
33. P. maclura (Le Sueur). Burrerrty Ray. Disk nearly 
twice as broad as long, three times as long as tail; sting on tail 
usually obsolete. Olive-brown, finely marbled and speckled ; tail 
with four dark blotches: front edge of disk with pale half-circular 
spots. Va.S. (To William Maclure.) 
Famity XVII AETOBATIDA. (Tue Eacte Rays.) 
Pectoral fins interrupted, reappearing on tip of snout as one or 
two detached appendages or cephalic fins; skull somewhat elevated, 
so that eyes and spiracles are lateral; teeth large, flat, hexangular, 
