472 



HOLOCEPHALI 



[CH. 



The notochordal sheath is not broken up into centra, but in 

 Chimaera it has developed within it a large number of calcified 

 rings, three to five times as numerous as the neural arches. 



The Holocephali were 

 once a numerous group ; 

 now they are represented 

 by a few genera, of which 

 the best known is Chi- 

 maera, sometimes called 

 the Rabbit-fish, common 

 to the Mediterranean and 

 to the Atlantic coast of 

 Europe and Africa. C. 

 monstrosa is found on the 

 east coast of N. America. 

 On the Pacific coast (7. 

 collei occurs in such num- 

 bers as to be a serious 

 nuisance to fishermen. It 

 eats the baits off their 

 lines. It is known as the 

 Rat-fish, in allusion to 

 the shape of the tail. Cal- 

 lorhynchus occurs in the 

 temperate waters of the 

 Southern Hemisphere. A 

 third genus, Harriotta, is 

 a deep-sea form, and quite 

 recently another deep-sea 

 genus Rhinochimaera with 

 an enormously developed 

 rostrum has been found off 

 the west coast of Ireland 

 just on the slope where 

 the shallower inshore water 

 passes into the abysmal 



. 231. Chimaera moii&troisa, L. depths of the Atlantic. 



Male with process on snout. Seduced. Fr0m tne character of 



their dentition one would 



naturally conclude that the Holocephali normally fed on food which 

 required a good deal of mastication, and if this be so we can 



