12 Mr. P. W. Bassett-Smith on 



mandibles finely dentate on convex border ; first maxilliped 

 long, bifid at end, outer claw very long ; second maxillijjed 

 small, with simple claw ; maxillary palp long and sharp ; 

 furcula small, simple, with widely divergent branches. First 

 perseopods with three very long plumose setae on the inner 

 border and four short bristles at end of last joint ; second 

 pera3opods bifid, each two-jointed, bearing very long plumose 

 setffi ; third perteopods bifid, each branch two-jointed; hamu- 

 lus posterior well marked ; fourth pera^opods almost rudi- 

 mentary, represented by minute basal joint, three times as 

 long as broad, terminating in three short simple bristles. 



Genital segment nearly square, lobed at posterior angles, 

 bearing a tubercle giving rise to three simple setge (repre- 

 senting five pairs of limbs ?). 



Abdomen small, slightly longer than broad ; caudal plates 

 of moderate size, bearing one short and three long plumose 

 setaj ; ovarian tube long, straight. 



Lepeophtheirus poUachiuSj sp. n. (PI. IV. fig. 1.) 



Both sexes taken in quantity from the palate and back of 

 the tongue of Gadus poUackius, also from the gills of the ling, 

 Molva vulgaris. This species is nearly allied to L. Stromii^ 

 Baird. 



Carapace oval, rather wider posteriorly, in some specimens 

 broader than long ; fourth joint of the thorax large, diamond- 

 shaped ; genital segment oblong, nearly as large as the cara- 

 pace, lobed posteriorly ; abdomen as long as the thorax, 

 tapering off towards its extremity. Posterior antennee large, 

 strongly hooked ; palp short, acute. Hamulus anterior small ; 

 furcula with short, divergent, simple branches ; fourth pair of 

 perseopods very long and powerful. Male much smaller than 

 female, with elongated carapace and very narrow genital 

 segment. Abdomen distinctly divided into two segments 

 and caudal plates very long. 



In many instances the young forms in various stages of 

 development were found attached by their thread-like fila- 

 ments to the margins of the carapace, genital segment, and 

 abdomen of the female. 



Elytropliora hrachyptera, Gerstaecker. (PI. IV. fig. 3.) 



From the gills of a large tunny, Thynnus thynnus, taken 

 outside Plymouth, I obtained ten specimens of this species, 

 five of each sex, all alive. These I watched for several hours 

 in a bell-glass. They were very active, and the males were 

 seen to attach themselves to the females in the positions 



