32 Transactions. — Zoology. 



Class CKUSTACEA. 



Order Copepoda. 

 Genus Anthosoma. 



The head is of tolerable size, and distinct, consisting of a 

 stout, rather narrow and strongly convex, horny buckler, of an 

 ovoid shape. It is very narrow, thick, and obtuse in front, 

 where it has a furrow running across its dorsal surface, and a 

 deep notch on each side, which thus forms a beak, and almost 

 divides it into a separate segment. It extends backward for 

 some length, and becomes considerably broader, covering a 

 portion of the thorax. 



The segments of the thorax are very indistinct. On the 

 dorsal aspect are two foliaceous elytraform appendages of an 

 oval shape, and of a light horny and granulated texture. Be- 

 neath these the remaining portion of the thorax is seen, of a 

 fleshy structure, and apparently without divisions. 



The abdomen is very small, consisting of one short segment, 

 which gives off two small caudal appendages in the form of 

 short, flat, blunt filaments of the same texture as the elytraform 

 appendages. Immediately beneath the notch, on each side of 

 the blunt peak, we see a small flat body, and from near the 

 base of each of these we find the origin of the antennae. These 

 organs are rather long and slender, and consist of six articu- 

 lations, tapering from the base to the extremity. The most 

 remarkable organs attached to the head, however, are the first, 

 pair of foot-jaws. These arise from between the base of the 

 antenna?, are very long and strong, and project forward beyond 

 the head. They consist of three stout joints of considerable 

 length, and of cylindrical shape ; the second joint, near its 

 apex, having a tooth or spine, the last being terminated by a 

 curved hook, which points upwards and backwards. The second, 

 of three joints also, is of nearly equal length, but much more 

 slender, and has the terminal joint ovate, compressed, and bifid. 

 The third pair is short, very thick, stout, of two joints, and 

 terminates in a strong claw-shaped extremity. The feet are 

 three pairs, and are all foliaceous. The structure of these 

 members is very simple, being merely foliaceous lamelkp, which 

 lap over each other and surround the thorax as with a shield. 

 They are of a light horny texture and somewhat granulated, 

 like the dorsal elytraform appendages. The oviferous tubes are 

 straight and very long. (Band, " Brit. Ent.," p. 298.) 



The form of the feet and structure of the foot-jaws indicate 

 that this animal is capable of little motion, and lives a strictly 

 parasitic existence. It Imries its beak in the fiesh of its host, 

 and thereby causes him much irritation, as evidenced by the 

 iufiamed appearance of the parts attacked. 



