80 BRITISH PARASITIC OOPEPODA. 



frontal plates ; antennas small with weak terminal 

 claws. The terminal claws of the second maxillipecls 

 of moderate size. The first four pairs of thoracic legs 

 all biramose, and the rami biarticulated and furnished 

 with plumose setas, the first and fourth pairs with very 

 small basal joints, those of the second and third con- 

 siderably expanded. Egg-strings very long and slender, 

 and looped so as to appear as if they each consisted of 

 three strands. 



Male. The male, which is of the usual Nogaus form, 

 is somewhat similar to the female, but the suborbieular 

 carapace is proportionally larger, being equal to at 

 least three-sevenths of the total length. The first 

 free thoracic segment fills the space between the lateral 

 prolongations of the carapace, and is slightly produced 

 into small rounded lobes which are contiguous with 

 the lobes of the carapace. The next segment is small, 

 while the third (the fourth counting the carapace) is 

 without dorsal plates. Genital segment oblong, rather 

 longer than broad, width equal to fully one-third the 

 width of the carapace, and having the postero-lateral 

 corners slightly produced and rounded. Abdomen 

 small, two-jointed ; caudal rami large and lamelliform, 

 longer than broad and furnished with small spiniform 

 setas on their truncated distal extremities. Cephalic 

 appendages somewhat like those of the female, but the 

 second maxillipeds are short and tolerably stout, bear- 

 ing stout terminal claws ; the thoracic legs are also 

 similar to those of the female. Length variable, 

 about 13 to 16'5 mm. 



Habitat. Parasitic on dog-fishes. On a dog-fish 

 captured off the Xorth of Ireland. Belfast Bay (IT. 

 Thompson, ' Nat. Hist, of Ireland,' vol. iv, 1856). 



We have not seen this species. Our figure of it is repro- 

 duced from that of Otto referred to above. 



C. B. Wilson, after a critical examination of the characters 

 of Nogagus grandis Steenstrup and Liitken, remarks it is 

 " fairly certain " that this Nogagus is the male of Demoleus 

 paradoxus (Otto). 



