PIFTEEN-SPINEll STICKLEBACK. 
183 
A nest selected 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 cjuitting 
itie 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 dififcrcnt 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 feUows as 
fell dead to the bottom of the vessel in which they were 
confined. 
This species is capable of great activity, and when^ m cap - 
tivity I have known it to throw itself over the brim of a 
vessel where the water was three inches beloiv 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 midway between the snout and eyes, 
and appearing to exert a sensitive action when the fish is at 
