THE BAFFIN’S BAY A RCTUR US. 477 
fro. Ever and anon the blade is shut forcibly upon the grooved haft, and woe be to the 
unfortunate infusorium, or mite, or rotifer that comes within that grasp ! The whole action, 
the posture, figure of the animal, and the structure of the limb, are so closely like those of the 
tropical genus Mantis among insects, which I have watched thus taking its prey in the 
Southern United States and the West Indies, that I have no doubt passing animals are caught 
by the crustacean also in this way, though I have not seen any actually secured. 
“The antennae, too, at least the inferior pair, are certainly, I should think, accessory 
weapons of the animal’s predatory warfare. They consist of four or five stout joints, each of 
which is armed on its inferior edge with two rows of long, stiff, curved spines, set as regularly 
as the teeth of a comb, the rows divaricating at a rather wide angle. From the sudden 
clutching of these organs, I have no doubt that they too are seizing prey ; and very effective 
implements they must be, for the joints bend down towards each other, and the long rows of 
spines interlacing must form a secure prison, like a wire cage, out of which the jaws 
probably take the victim, when the bending in of the antennae has delivered it to the mouth. 
“ But these well-furnished animals are not satisfied with fishing merely at one station. As 
I have said above, they climb nimbly and eagerly to and fro, insinuating themselves among 
the branches, and dragging themselves hither and thither by the twigs. On a straight surface, 
as when marching (the motion is too free and rapid to call it crawling) along the stem of the 
zoophyte, the creature proceeds by loops, catching hold with the fore limbs, and then bringing 
up the hinder ones close, the intermediate segments of the thin body forming an arch, exactly 
as the caterpillars of metric moths, such as those, for example, that we see on gooseberry 
bushes do. But the action of the crustacean is much more energetic than that of the 
caterpillar. Indeed, all its motions strike one as peculiarly full of 
vigor and energy. 
“I have seen the large red species swim, throwing its body into a 
double curve like the letter S, with the head bent down, and the hind 
limbs turned back, the body being in an upright position. It was a 
most awkward attempt, and though there was much effort, there was 
little effect.” In our illustration the creature is enlarged. 
The Whale-louse is, like all the species of this genus, parasitic, 
residing on the whale and dolphin. Their hooked and diverging legs, 
armed with their sharply-curved claws, enable them to cling so tightly 
that not even the swift movement through the water, or the active 
exertions of the creature on which they reside, are sufficient to shake 
them from their hold. The different species of Whale-louse seem to prefer various parts of the 
body, one species clinging to the head, another to the side, and another to the fin. They all 
burrow rather deeply into the rough and thick skin of these marine mammalia. 
Their bodies are flattened and rather oval ; they have five pairs of legs, all prehensile ; 
and on the second or third joint of the thorax, instead of legs there are long appendages for 
respiration, which usually are bent over the back. The illustration is of natural size. 
ISOPOD A. 
Ix the Isopod Crustacea, the signification of which word has already been given, there is 
a great resemblance to the common wood-louse, and many of them might easily be mistaken 
for those common and destructive beings. The females have large homy plates on their legs, 
so formed as to produce a large pouch under the thorax, wherein the eggs are contained. In 
many species some of the rings of the abdomen are connected so as to resemble a single joint. 
The Baffin’s Bay Arotueus is one of the best developed of the whole order. In all the 
species belonging to this genus the body is long, and the first four pairs of legs are beautifully 
feathered at the ends. These cannot be used for walking, the three last pairs of legs being 
devoted to this purpose. The long antennae are used as organs of prehension, and with them the 
creature captures its prey. The young are said to cling by their legs to the antennae of the parent. 
WHALE-LOUSE. Cyamu 4 
ovalis. 
