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CARTILAGINEIo — RAIAD^. 
Ray, the whole canal of whose intestine is not 
more than half as long as the stomach.” 
3. Raiana. The Skates. The rhomhoidal or 
lozenge-shaped outline, is eminently character- 
istic of this group, which is the most numerous 
of the whole. The tail is moderately long and 
slender ; furnished with two small dorsals, and 
generally terminated by a small caudal. The 
skin on the upper parts, particularly of the tail, 
is generally studded with asperities, tubercles, or 
curved prickles, but never armed with a long, 
serrated bony spine. Eleven of our British spe- 
cies belong to this group. 
4. Trygonina. The Sting-rays. In these the 
head is surrounded and inclosed by the pectoral 
fins ; the disk is somewhat rounded ; the tail is 
long, and drawn out to a fine point ; it is quite 
destitute of fins, but is armed near its base with 
a long and sharp, fiattened, bony spine, the two 
sides of which form thin edges, cut into close, acute 
teeth, — a most formidable weapon. We have one 
British species, commonly called the Eire-fiaire, 
of which Mr. Couch thus speaks. The man- 
ner in which it defends itself shows its conscious- 
ness of the formidable weapon it carries on its 
tail. When seized or terrified, its habit is to 
twist its long, slender, and fiexible tail round 
the object of attack, and with the serrated spine 
tear the surface, lacerating it in a manner calcu- 
lated to produce violent inflammation.” Other 
authors state that it is capable of striking its 
weapon with the swiftness of an arrow into its 
prey or its enemy, when, with its winding tail, 
it secures its capture. 
5. Myliohatina. The Eagle Rays. The pec- 
