FIFTEEN-SPINED STICKLEBACK. 183 



A nest select^ for observation had its outer case formed of 

 green sea-weeds, within which were short pieces of brown 

 weeds; and, contrary to the usual custom, it was watched 

 by a couple of these fishes. At the precise time of quitting 

 the egg, the young were placed under a magnifier of moderate 

 power, when it was observed, that instead of a long protruded 

 snout, the form of the head was round and blunt, the pec- 

 toral fins were large, and a dorsal fin passed along the greater 

 part of the back to be united to the caudal fin, from which 

 again it advanced to form an anal fin. In some examples 

 this union was by an uninterrupted border, but in others 

 there was a notch at the place where the dorsal and anal 

 fins came together. The belly was protuberant, and in some 

 the ovum was still visibly attached to the body; and as the part 

 of union was diaphanous, globules could be seen, that had 

 passed from the egg to the intestine. No ventral fins could 

 be perceived, which is less a matter of surprise that it has 

 been observed in other instances — these organs are the last 

 that go through the process of development. The truly apodal 

 fishes (such as are always without ventral fins, as the Conger,) 

 are, in fact, in a condition of arrested development in this 

 particular. How widely different is this form from that of the 

 parent! and yet, when half an inch in length, the lineaments 

 are perfect. These little newly-born fishes were active and 

 voracious, for they eagerly attacked such of their fellows as 

 fell dead to the bottom of the vessel in which they were 

 confined. 



This species is capable of great activity, and when in cap- 

 tivity I have known it to throw itself over the brim of a 

 vessel where the water was three inches below it. It feeds 

 on crustaceous animals, and indeed on any animal substance 

 it is able to swallow; and I have known it to attack and 

 partially devour an eel of three inches in length, which, 

 however, it was compelled finally to reject. 



The usual length is about six inches; the head compressed 

 at the sides, wide and flat on the top, lengthened before the 

 eyes, which are moderately large and brilliant. Under jaw 

 the longest; both have teeth; the lips fleshy; tongue far back 

 in the gullet. Nostrils mid way between the snout and eyes, 

 and appearing to exert a sensitive action when the fish is at 



