RAYS 59 



distributed in the Indian and Pacific Oceans. It has a broad, 

 rounded snout, the first dorsal fin is above the pelvics, and 

 there are several rough ridges composed of enlarged denticles 

 on the head and neck. The whole of the upper surface is 

 covered with numerous round, white spots, and there are 

 also some darker and paler bars, but all these markings tend 

 to become obscure in large individuals. 



The Ulavi or Plough-headed Ray (Rhynchobatus) , with one 

 species in the eastern Atlantic and another in the Indian and 

 Pacific Oceans, also has the first dorsal fin well forward, but 

 the snout is rather long and pointed and the enlarged denticles 

 are smaller and confined to the region of the snout, eyes and 

 spiracles, the shoulders, and the middle line of the back. The 

 young have 2 vivid eye-like spots on the body near the bases 

 of the pectoral fins, and there are a number of more or less 

 symmetrically arranged white spots on the body and tail, 

 but these markings are wanting in full-grown examples. 



The genus of true Guitar-fishes or Fiddler Rays (Rhinobatus) 

 includes a number of spe3ies from most warm seas, some small, 

 others growing to a b.rge size. Here the first dorsal fin lies 

 well behind the pelvics, and the tail is much reduced in size, 

 with the lower lobe less evident. The shape of the snout 

 and the coloration varies in the different species. 



The Guitar-fishes swim about slowly near the bottom, or 

 lie half buried in the sand or mud. When swimming, the 

 muscular tail is used as the organ of propulsion, the pectoral 

 fins being employed to raise or lower the body or for purposes 

 of turning and banking. Their food seems to consist mainly 

 of small fishes, crustaceans, shellfish and other ground-living 

 animals, which they crush with the tooth-bands made up of 

 numerous small, rounded teeth, set close together in pavement 

 fashion. The bands of teeth in the Mud Skate have a curious 

 shape, that of the uppei jaw being alternately hollowed out 

 and swollen, and that of the lower jaw provided with corre- 

 sponding bumps and depressions to fit into the upper (Fig. 

 59). The jaws of the Ulavi are much less wavy in outline, a 

 single swelling in the middle of the lower jaw fitting into an 

 indentation in the upper ; in the Guitar-fishes the tooth 

 bands are quite straight. 



Some of the Indian Guitar-fishes are said to live in large 



