68 FISH CULTURAL ASSOCIATION. 
and perhaps twenty others, but the above are the principal 
fishes in point of value. 
It is interesting to note that none of these fishes enter fresh 
waters in the Northern States,and it immediately raises the ques- 
tion why they do so in Florida? - Possibly it is only in the 
winter time, as the large striped bass (rockfish) run up the Hud- 
son at the same season ; probably an instinct connected with hiber- 
nation, as it is certainly not for food or the purpose of spawning. 
It would be interesting to know out of all this class of fishes, for 
which I have proposed the name Amphiectous, how many would 
breed in their new home; for while a salmon or a shad might 
exist for years in salt water, I would be surprised to learn that 
their eggs would hatch in the water of the ocean. According to 
Eckstrome, species of the pike-perch. Stzostethium ; the miller’s 
thumb, Cottus gobio; the ling or eel pout, Lota vulgaris, and a 
species of Acerina, a perch-like Ash, were found in the brackish 
waters of the Baltic Archipelago. In the Caspian sea Eichwald 
found a species of Cyprinus; the pike, “sox luctus ; the common 
river perch, Perca fluviatilis ; the loach, Codztus fosstlus, and a 
Stizostethium. Of mammals, birds, reptiles, crustaceans, mollusks 
and worms I have taken no account, for although not foreign to 
the subject, they would tend to swell this paper beyond its limits. 
It does not appear that it is due to any toxic action that some 
fresh water fishes die in salt water, but rather a difference in 
the density of the fluids, just as we would die in a short time 
under the great pressure to which sub-marine divers are subject- 
ed. The reverse would occur in salt water fishes when intro- 
duced into fresh water. They would then resemble ourselves 
on mountain tops where the blood is forced by internal pressure 
from the nose and ears, and the “baloon sickness” is felt. A 
French investigator, M. Paul Bert, has examined the causes of 
death in fishes and reptiles when changed from fresh to salt 
water, and is of the opinion that the cause does not reside in any 
poisonous quality of sea water, but is simply a phenomenon of 
osmosis, or transmission of fluids through the membranes ; or; 
in other words, absorption of a heavier fluid in a membrane al- 
ready filled with a lighter one. An example is cited of a frog 
which, when plunged into sea-water, it is claimed, loses one- 
