RAYS. 



109 



Oceans ; three of them are rather common in the Mediterranean, 

 and one {T. hebetans) reaches the south coast of England. They 

 attain to a width of from two to three feet, and specimens of that 

 size can disable by a single discharge a full-grown man, and 

 therefore may prove dangerous to persons bathing. 



The Raiida, or True Rays (Case 43) , have a wide geographical [Case 43.] 

 range ; they are chiefly inhabitants of temperate seas, and much 

 more numerous in those of the northern than of the southern 

 hemisphere. More than 30 species of the genus Raia are known, 

 of which the following are found on the British coasts : — The 



Fte. 97. 



- ' 



%/;w, 



Sting-Ray (Trygon uarnak). (From Madras.) 



Thornback (R. clavata), the Homelyn Ray (R. maculatd), the 

 Starry Ray (R. radiata), the Sandy Ray (R. circularis), the 



