RIVER GARDENS ; 
last of tlie species frequenting the fresh as well as 
salt water is G. pungitius , the ten-spined Stickle¬ 
back, a very distinct species, much smaller than 
any of the preceding. Cuvier makes a second 
species in the ten-spined division; hut it is not found 
in England. There is, however, one more native 
kind, the fifteen-spined, which remains always in 
the sea, but, like its relatives, will live in fresh 
water. If, therefore, it can be procured, it should 
be present, to complete the collection of native 
species in an Aquarium, for which purpose I would 
recommend preparing a special tank, which, consi¬ 
dering the interesting habits of this pretty tribe of 
miniature fishes, would well repay the trouble. The 
last-named species, though a thoroughly well-charac¬ 
terised Gasterosteus , is of very peculiar form, almost 
Eel-like in his proportions, from which it has been 
termed the Sea Adder. Mr. Yarrell gives a very in¬ 
teresting account of the capture of a specimen of this 
rather rare species, in the stomach of which he found 
a specimen of the curious Opossum Shrimp, which he 
had never seen before. The peculiarity of the Opos¬ 
sum Shrimp, as described by Montague, is that the 
female is furnished with a natural external pouch, 
like that of the Opossum or Kangaroo tribe, in 
which she carries her ova and afterwards her young. 
70 
