new Parasitic Copepods on Fish. 87 



Female. — Carapace as broad as long, narrowing rapidly 

 in front, where is seen the rather deep frontal plate, exca- 

 vated considerably in the middle. 



Anterior antennce : first joint short and thick, with many 

 plumose hairs on the anterior border ; the second much longer, 

 cylindrical, with a tuft of hairs at the end and one near the 

 middle of the lower border. Posterior antennce of moderate 

 size. Hamulus has a rather dilated base, with short curved 

 claw. Palp with two slightly divergent branches, both 

 sharply pointed, the inner being the longer. Maxillipeds not 

 remarkable. Furcula small, with very short, pointed, slightly 

 divergent, simple branches, the base strong and broad, on 

 either side having a double root. 



First perceopod : the basal joint is short, the second cylin- 

 drical, and the palm bears three short end-claws, a long 

 bristle at the angle, and three long plumose hairs from the 

 lower border. 



Second perceopod : the upper border of the first two joints 

 of the outer branch bears each a single short spur, the third 

 or last joint has two. 



Third perceopod : the lamellar plate is large, the branches 

 are placed close to one another, but not overlapping. 



Hamulus posterior of moderate size, claw slightly bent. 

 Last thoracic segment very large. 



Fourth percvopods long and strong, distinctive of the species, 

 consisting of four joints : the first long, cylindrical, and 

 muscular ; second to fourth fused, long, narrow, with parallel 

 borders, the under being finely ciliated ; from the last joint 

 are three long curved hook-claws, the outer being much the 

 longest, from the third joint a fourth, but less long, and 

 from the second an extremely short one is visible. 



Genital segment almost a perfect sphere; near the posterior 

 edge are seen the rudiments of the fifth feet in the shape of a 

 small tubercle with three hairs from it. Abdomen very short, 

 one quarter the length of the genital segment, single-jointed, 

 broadest near the centre, narrowing posteriorly. Caudal 

 plates small, broader than long, with three terminal plumose 

 hairs, and a shorter one on the outer border. 



Length 4-5 millim. 



Male. — Cephalothorax large, more than two thirds the 

 length of the whole, oval, widest posteriorly, last thoracic 

 joint not so large as in the female. Genital segment deeply 

 excavated behind, causing the appearance of two lobe-like 

 prolongations, each of these terminating in a long papilla, 

 ending in a strong bristle, with two smaller ones on the 

 inner border. 



