RATA. 313 
II.—RAIA. 
PHYLUM = CHORDATA (p. 403). 
Sus-PHYLUM VERTEBRATA (p. 406). 
Cass Pisces (p. 435). 
Raia radiata* is one of the commonest of the British 
skates, and is perhaps the most convenient as regards size. 
The other species only differ in size, colour, general shape 
of the body and other small structural features. 
The skate lives near the bottom at moderate depths, 
and is carnivorous in diet. In shape its body is rhomboidal, 
Externay With a long tail depending from one angle. The 
body is flattened dorso-ventrally, the two large 
side-flaps being made up of the enormously 
expanded jectoral and fairly large pelvic fins. Attached 
Features. 
Fig. 226.—JAwWs AND TEETH OF (A) MALE AND 
(B) FEMALE SKATE. 
serum 
to the pelvic fins in the male is a pair of large c/aspers. 
These fins represent the front and hind-limbs respectively 
of the higher Vertebrata. 
The pointed anterior end is termed the rostrum. 
* The following. description will apply for the Common British species, Rusa 
maculata and Raia batis. i g 
