The True Sharks 551 



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 Rhinobatns. The best-known 

 American species are Rhinobatns lentiginosus of Florida and 

 Rhinohatus prodnctus of California. The names guitar-fish, 

 fiddler-fish, etc., refer to the form of the body. Numerous 

 fossil species, alhed to the recent forms, occur from the Jurassic. 

 Species much like Rhinobatns occur in the Cretaceous and Eocene. 

 Taniiobatis vetnstns, 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, Tamiobatida:. It is more likely a shark however than 

 a ray, although the skull has a flattened ray-like form. 



Fig. 343. — Guitar-fish, Rhinohatus lentiginosus Garman. Charleston, S. C. 



Closely related to the RJiinobatidw are the Rhinida (Rham- 

 phobatidce), a small family of large rays shaped like the guitar- 

 fishes and foimd on the coast of Asia. Rhina ancyiostoma 

 extends northward to Japan. 



In the extinct family of Astrodermidce, allied to the Rhino- 

 batidcE, the tail has two smooth spines and the skin is covered 

 with tubercles. In Belemnobatis sismonda: the tubercles are 

 conical; in Astrodermns platypterns they are stellate. 



Rajidae, or Skates. — The RajidcE, 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 



