326 FISHES. [Cuar. X. 
the eastern coast of the island, where it attains a 
length of from twelve to fifteen feet, including the ser- 
rated rostrum from which its name is derived. This 
HEAD OF THE SAW-FILSH (PRISTIS ANTIQUORUM) 
powerful weapon seems designed to compensate for the 
inadequacy of the ordinary maxillary teeth which are 
unusually small, obtuse, and insufficient to capture and 
kill the animals which form the food of this predatory 
shark. To remedy this, the fore part of the head and 
its cartilages are prolonged into a flattened plate, the 
length of which is nearly equal to one third of the 
whole body; its edges being armed with formidable 
teeth, that are never shed or renewed, but increase in 
size with the growth of the creature. 
The Rays form a large tribe of cartilaginous fishes 
in which, although the skeleton is not osseous, the de- 
velopment of organs is so advanced that they would 
appear to be the highest of the class, approaching nearest 
to amphibians. They are easily distinguished from the 
sharks by their broad and flat body, the pectoral fins 
being expanded like wings on each side of the trunk. 
They are all inhabitants of the ocean, and some grow 
to a prodigious size. Specimens have been caught of 
twenty feet in breadth. These, however, are of rare 
