THKEE-SPINED STICKLEBACK. 
175 
througli the middle of it; and on each side of the origin of 
this flat plate or ventral shield, (which in some degree serves 
the jmrposc of a sternum, as Avell as a defensive armour for 
the breast,) is a sharp sphie of considerable length, and 
finely serrated on its upper border or edge. This formidable 
sj^ear is in fact one of the two which serve to spread the 
membrane of the ventral fins, but it is the weapon with which 
all the deadly contests of this fish arc conducted. There is a 
slight spine in front of the anal fin. '^I'he dorsal and anal 
fins are on the hinder part of the body; and the origin of 
the latter is a little behind that of the former. The body 
grows slender as it approaches the tail, the latter organ in its 
folded state being concave. When dry the plates or shields 
before mentioned appear rough. Colour of the back olive 
brown, well defined on the sides; below, and on the fins and 
tail a dull yellow: the colours influenced, no doubt, by the 
spirit in which these fishes had been preserved. Formulce of 
the fin rays, — pectoral ten, dorsal fifteen or sixteen, ventral 
two, caudal eleven, with some small rays. 
Another example of the same variety, and about the same 
length, was of a much more slender form, and in other 
respects, different proportions, the dorsal and anal fins being 
also carried nearer to the tail; and in a third, which may be 
termed the Half-armed Stickleback, while the depth of body 
nearly answers to the example we first described, the dorsal 
and anal fins are reduced to much smaller dimensions, there 
is an elevated ridge near the side of the tail, and the tail 
itself is straight. The lateral plates in this variety never 
descend to join with the shield of the belly, and contract 
suddenly in dimension opposite the third dorsal spine. The 
colour of these fishes partakes of every variety, from sober 
brown to a brilliant green, with rcddhli or crimson tints. 
