196 THE STORY OF FiSH LIFE. 



their undoing. For the members of another 

 genus, Myxine, have acquired the habit of boring 

 into the victim's body and feeding thereon till 

 death puts an end to the long-drawn tragedy. 

 On account of this ghoulish practice this species 

 has been christened the hag fish. Now the 

 lampreys are, as we have already hinted, re- 

 garded by some as degenerate, a contention 

 which the living forms amply support. For we 

 can see how, by a very natural transition, a pre- 

 datory form has become degenerate by adopting 

 the method of the leech instead of the vigorous 

 attack of the shark, and how this leech-like 

 method has led to further degradation, ending 

 in the parasitism of the hag-fish. The evidence 

 for degeneration lies mainly in the absence of 

 jaws and paired fins. These may well have been 

 lost in consequence of the habit above described. 

 The loss of hardened scales or skin armour of 

 any kind, and the absence of bony matter in 

 the skeleton, may be further consequences of 

 their evil ways. There is certainly much to be 

 said for the degenerate theory, for dissection of 

 the lamprey in its early stages of development 

 reveals traces of a hardened skeleton. By way 

 of additional evidence in favour of this hypothesis 

 that the skeleton of the modern lamprey is de- 

 generate we may adduce the fact, that in the most 

 ancient known members of this tribe, the remains 

 of which occur in the old red sandstone of Caith- 

 ness, there was a well-defined vertebral column or 

 backbone, made up of calcified or hardened bone- 

 like vertebrae. This fossil was discovered and 

 has been described by Dr Traquair, and named 



