SOME RARE OR UNCOMMON FISHES 273 



exactly like that of typical sharks. Affinities are also seen with 

 the lung-fishes, in the solid skull, with the jaw attached directly 

 by its own substance. 



Our own chimera, which also occurs in the deeper parts 

 of the Mediterranean, is the largest of surviving chimaeroids. 

 Four small ones, the largest measuring 16 in., were taken by 

 the Travailleur at a depth of from 800 to 1,200 metres. 

 It has the cartilaginous skeleton, and on each side a single gill- 

 opening covered by a fold of skin that forms a rudimentary 

 gill-cover, the outlet of four gills. The body is long, ter- 

 minating in the aforementioned attenuated and apparently 

 degenerate tail. There is a fringed filament over the snout, 

 and on the head are rows of pores, the use of which has not 

 been explained. The pectoral fins are large and fan-shaped ; 

 the tail is as long as, or longer than, the body. The adult has 

 no scales, but the younger stages are said to possess small, 

 tooth-like scales, locally distributed. In colour the chimasra is 

 brown and silvery. 



The chief difference between chimasroids and sharks lies in 

 the teeth. In sharks, as we have seen, they lie in numerous 

 rows, unconnected by ossification with the gristly jaws, those 

 behind being ready to take the place of the others when accidental 

 or natural causes shall have rendered these useless. The teeth 

 of chimseroids, on the other hand, are soHd-looking molars on 

 the palate and lower jaw, with a small pair of cutting teeth in 

 the upper jaw, on the front edge. They are clearly intended 

 for triturating food, and it is probable that crustaceans and 

 molluscs, rather than herrings, form the bulk of the chimasra's 

 prey. The lateral line, sharklike, is distinct, but the air-bladder 

 is wanting. 



The breeding of the chimaera has not been studied, for 

 the difficulties are at present insuperable. The fish has never 

 been kept in captivity, and its natural haunts are too far 

 removed from the eye of man for there to be much hope of an 

 early explanation of the many mysteries of its life. Wc can 



18 



