DEEP-SEA FAUNA. 145 



them were free and unattached. Now, in past 

 times in the history of the earth different genera 

 and species of stalked Crinoids or Sea-lilies were 

 very plentiful, and from their abundance in 

 certain geological deposits, it is believed that 

 they lived in enormous numbers. The dis- 

 covery of the new genera of stalked Crinoids 

 in the abyss suggested that possibly there 

 might be found several other families of ex- 

 tinct animals still surviving in the deep sea. 

 This view was supported by the Heart-urchin, 

 whose shell showed some striking peculiarities 

 that were only known in fossil genera. 



But the hopes that were felt, even if they were 

 not always expressed, were doomed to disap- 

 pointment. No living Ichthyosauruses or Plesio- 

 sauruses, none of the remarkable Ganoid fish of 

 Devonian times, no Trilobites, no Cystoids nor 

 Blastoids, in fact none of the most interesting of 

 the fossil types rewarded the investigators of the 

 Challenger and subsequent expeditions. 



It is perfectly clear to us now that, taken as a 

 whole, the deep-sea Fauna is not more ancient in 

 character than any other Fauna. It is true that 

 a few genera, such as those just referred to, havr 

 survived, probably from very ancient times, with- 

 out much modification ; but the vast majority of 

 forms are simply shallow water animals, which 

 have been profoundly modified in structure, and 

 adapted to the peculiar conditions of existence in 

 the great depths of the ocean. 



