154 THE FAUNA OF THE DEEP SEA 



hyperborea, has been found in water extending from 

 400 to 608 fathoms in depth. Only four specimens 

 have yet been taken, one by the Norwegian expedi- 

 tion off Spitzbergen and three by the ' Knight 

 Errant ' off the northern coasts of Scotland. It is 

 interesting to find that this, the only deep-sea species 

 of the Rays, shows some striking peculiarities. ' The 

 teeth are remarkably slender,' says Giinther, ' small, 

 irregularly and widely set, different from those of other 

 British Rays. In young specimens at any rate those 

 of the male do not differ from those of the female. 

 The mucous membrane behind the upper jaw forms 

 a pad with a lobulated surface. The mucous cavities 

 of the head are extremely wide, and finally the acces- 

 sory copulatory organs have a spongy appearance, 

 and are flexible, the cartilage by which they are sup- 

 ported being a simple slender rod.' 



The other Elasmobranch, that extends into very 

 deep water, is Chimcera affinis, a species which can 

 hardly be distinguished from the better known 

 Chimcera inonstrosa, a fish that itself very frequently 

 wanders within the limits of the abysmal zone. 



Among the Teleostei, the family Berycidas has 

 several representatives in the deep water. They are 

 small fish rarely exceeding four inches in length, with 



