31 
Cod is in large part easy of acquisition, and could also be 
well represented in separate series of aquaria. The fauna 
south of Cape Hatteras and that of the western coasts of 
the United States, and other faunas, could also be exhib- 
ited, as opportunities presented themselves, either to a 
limited degree or more or less extensively, if the future 
progress and success of this division warranted the 
extension. 
II. Fresh Water Aquarium. 
It is obvious that an epitome collection is as desirable 
for the explanation of the relations of fresh-water plants 
and animals as of the marine. 
1. The Society would therefore form an epitome col- 
lection similar to that planned above for the Marine Aqua- 
rium ; but this would necessarily differ in the details of 
its composition, fresh-water plants and animals being used 
instead of marine types. The adaptations of the structures 
of organisms to an aquatic existence would be exhibited by 
means of preparations of the gills, etc., as in the correspond- 
ing marine collection ; but special adaptations to a fresh- 
water existence, such as the mode of reproduction of 
sponges, bryozoa, and some crustaceans by means of 
winter buds, the effects of desiccation upon some of these, 
and their mode of transportation from pond to pond, the 
contrasted structures of corresponding fresh-water and 
marine shrimps, the peculiarities of the batrachians, showing 
the transitions from a purely aquatic to a terrestrial type, 
and similar classes of facts would be prominently illustrated. 
The fresh-water faunas of the globe are all secondary, or 
derived mainly from the marine faunas. This can also be 
approximately demonstrated in the epitome collection by 
placing side by side a certain number of marine and fresh- 
water animals in series or in pairs, including occasionally 
