1885.] Recent Literature. 1193 
enable it to inhabit fresh water, and it is concluded: “If an ani- 
mal so exceedingly intolerant of fresh water as is a marine jelly- 
fish may yet have all its tissues changed so as to adapt them to 
thrive in fresh water, and even die after an exposure of one 
minuté to their ancestral element, assuredly we can see no reason 
why any animal in earth or sea, or anywhere else, may not in 
time become fitted to change its element.” 
The book closes with an interesting chapter on the movements 
\ 
FU 
Fic. 5.—The fresh-water Medusa. Enlarged. 
of star-fishes. And here it may be said that at the time this por- 
tion was written the later discoveries as to the nature of the ner- 
vous system of crinoids had not been published. It is now 
known, by the experiments of Marshall and Jickeli, as well asthe 
histological investigations of the two Carpenters, that the visible 
nerves in crinoids belong to a general subcutaneous nervous 
sheet. 
The well-known movements of the star-fish are then described 
and well illustrated (Fig. 6), as well as the natural movements of. 
