RIVER GARDENS; 
manner at the bottoms of brooks, and all its move¬ 
ments and habits, in pursuit of its prey, and other¬ 
wise, are curious and amusing. 
From the Water Spider to the Crab, Shrimp, and 
other crustaceans, is hut a step; they are so similar 
in many points of their structure. The fresh-water 
Shrimp is worthy of a place in the Aquarium, on 
account of his peculiar method of swimming, hut is 
so inconspicuous that few would take much in¬ 
terest in his proceedings on that account. Other 
small fresh-water Crustacea are curious as micro¬ 
scopic objects, hut scarcely desirable for the 
Aquarium; I therefore pass to the only con¬ 
spicuous member of the family who has conde¬ 
scended to honour the fresh water with his pre¬ 
sence. This is the Cray Fish of our brooks and 
trout-streams—the Astacus fluviatilis. He is 
somewhat difficult to manage, hut many have 
failed, it would seem, in consequence of placing him 
in too deep a vessel, as Professor Bell, in his work 
on British Crustacea, describes one that was kept 
for a considerable time in a pan, only an inch 
and a half deep. A glass ledge might therefore he 
erected in the Aquarium, about that distance from 
the surface of the water, upon which a few pieces of 
rockwork might be formed into a retreat for the 
106 
