MUSEUM OF COMPARATIVE ZOOLOGY. 



455 



taliidic furnish nearly twenty-eight per cent of the species of the abyssal fauna 

 collected by the Blake. 



TABLE I. 



General Numerical Results. 



TABLE 11. 



Genera represented by more than one Species in the Abyssal Area. 



Total, 24 genera and 87 species. 



For the naturalist of to-day the most interesting feature of abyssal life is 

 not that it furnishes him with singular and archaic forms, useful in his study 

 of extinct genera ; nor the beauty and rarity of the creatures living under 

 such unusual conditions. The most important characteristic of abyssal life is, 

 that it, and it alone, exhibits a fauna in which reciprocal struggle is nearly 

 eliminated from the factors inducing variation and modification. There is no 

 mimicry or sexual selection where all is dark. In the struggle for life of the 

 abyssal animal, he is pitted against the physical character of his environment, 

 and not against his neighbor or the rest of the fauna. Hence we should have, 

 and really do have, the process of evolution less obscured by complications in 

 the abysses than is possible elsewhere. From a study of these animals in the 



