THE BAFFIN'S BAY ARCTUEUS. 



629 



much more energetic than that of the caterpillar. Indeed all its motions strike one as 

 peculiarly full of vigour 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.'' 



THE last figure on the illustra- 

 tion, marked D, is the creature 

 that is popularly known by the 

 name of WHALE-LOUSE. All the 

 species of this genus are 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 crea- 

 ture 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 and third joints of the tho- 

 rax, instead of legs there are long 

 appendages for respiration, which 

 usually are bent over the back. 



IN this illustration are several 

 of the Isopod Crustacea, the signi- 

 fication of which word has already 

 been given. In all the Isopods 

 there is a great resemblance to 

 the common woodlouse, and many 

 of them might easily be mistaken 

 for those common and destructive 

 beings. The females have large 

 horny 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 AECTUEUS is shown at fig. A, and 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 



A. BAFFIN'S BAY AEOTUBUS. Arciurus Ba/inii. 



C, D. .SHRIMP-FIXER. Bopyrus crangorum. B, P. IONE. Tone Ihorlcictu 

 B. FISH-LOUSE. Cymdthoe cestnim. 



