1884. | Zoology. 1053 
inthe same group, or order of catfishes, but in another family, 
aspecies of Chromis. And the same peculiar habit is likewise 
manifested by species of the same family living in South America, 
e Geophagi. The belief was also long current, and found ex- 
pression in most of the old books, that fishes not only did not take 
care of their young, but were invariably oviparous. We all know 
now how false such a statement is. In one class, the Selachians, 
the larger proportion of forms are viviparous. For example, of the 
sharks proper, three-fourths or more are viviparous, and the same 
statement holds good with respect to the rays or skates. Thus, 
out of 150 species of rays, over 100 are viviparous, and another 
noteworthy fact is that the oviparous rays are nearly all included 
in one family—the common skates or rays brought to our mar- 
ets. This feature of viviparity was known to the ancient natu- 
a Were viviparous, while all scaly fishes were oviparous. There, 
owever, he erred, for there is no such limitation. Many of the 
these cases were almost unknown. ` I agree with the statement of 
Mr. Ryder that confinement frequently affects the power of pro- 
dom in Zodlogical collections, but they do not bring forth young, 
their eggs are sterile. There are many exceptions to this rule, 
ut many cases of sterility for which we can assign no other 
cause. Somewhat analogous is the peculiar pathological condition 
of animals living in confinement, in which the bones become soft- 
ened or rickety.” 
