208 The True Sharks 
bottoms. The length of the snout differs considerably in 
different species, but in all the body is relatively long and strong. 
Most of the species belong to Khinobatus. The best-known 
American species are Rhinobatus lentiginosus of Florida and 
Rhinobatus productus of California. The names guitar-fish, 
fiddler-fish, etc., refer to the form of the body. Numerous 
fossil species, allied to the recent forms, occur from the Jurassic. 
Species much like Rhinobatus occur in the Cretaceous and Eocene. 
Tamiobatis vetustus, lately described by Dr. Eastman from a 
skull found in the Devonian of eastern Kentucky, the oldest 
ray-like fish yet known, is doubtless the type of a distinct 
family, Tum‘obatide. It is more likely a shark however than 
a ray, although the skull has a flattened ray-like form. 
Fic. 149.—Guitar-fish, Rhinobatus lentiginosus Garman. Charleston, S. C. 
Closely related to the Rhinobatide are the Rhinide (Rham- 
phobatide), a small family of large rays shaped like the guitar- 
fishes and found on the coast of Asia. Rhina ancylostoma 
. extends northward to Japan. 
In the extinct family of Astrodermuide, allied to the Rhino- 
batide, the tail has two smooth spines and the skin is covered 
with tubercles. In Belemnobatis stsmonde the tubercles are 
conical; in Astrodermus platypterus they are stellate. 
Rajide, or Skates.—The Rayid@, skates, or rays, inhabit the 
colder waters of the globe and are represented by a large number 
of living species. In this family the tail is stout, with two- 
rayed dorsal fins and sometimes a caudal fin. The skin is 
variously armed with spines, there being always in the male two 
series of specialized spinous hooks on the outer edge of the 
pectoral fin. There is no serrated spine or “‘sting,’’ and in 
all the species the eggs are laid in leathery cases, which are 
