96 BRITISH PARASITIC COPEPODA. 



lobes. Dorsal plates of the genital segment consider- 

 ably produced, their inner margins contiguous and 

 coalescent ; posterior corners prolonged into rounded 

 lobes, the space between the lobes being filled by a 

 suborbicular lamina which entirely conceals the 

 abdomen, while the caudal rami are seen projecting 

 one on each side of the median plate in the form of a 

 triangular process. 



Antennules small, partly concealed by the frontal 

 plates ; antennae also small, terminal claws slender 

 with an accessory spine on the inner margin. 

 Adhesion-disks four pairs. First maxillipeds slender, 

 joints subequal, terminal claws unequal ; second 

 maxillipeds considerably dilated. Thoracic legs 

 biramose ; the inner ramus in the first pair biarticulate, 

 the end joint being longer than the proximal one, and 

 with the apex broadly rounded and bearing a few 

 setas on the lower half of the inner margin ; outer 

 branch longer than the inner and composed of two 

 partly or wholly coalescent joints, the proximal part 

 being distinctly wider than the distal portion, which 

 is abruptly geniculated and tapers towards the apex ; 

 second and third pairs with both rami two-jointed ; 

 while in the fourth pair each ramus is composed of a 

 single joint. Length about 10 mm. 



Male. The male has a general resemblance to the 

 male of a Lepeophtheirus. The antennules are provided 

 with adhesive disks as in the female, but differ in 

 being armed with terminal claws ; the second maxilli- 

 peds are also furnished with distinct though small 

 claw-like hooks. All the four pairs of thoracic legs 

 are biramose with biarticulate rami ; the rami also 

 differ from those of the female in being provided with 

 moderately long and densely plumose setas. The 

 genital segment is subquadriform and equal to scarcely 

 one-fourth of the total length, and the abdomen is 

 composed of two segments. Length about 6 mm. 



Habitat. Parasitic on various dog-fishes and sharks : 

 Galens canis (Squalus galeusIAim.) ; Carcharias glauct'* : 



