NIKA COUCHII. 279 



curved. The fifth pair of legs are quite as loug", or a little 

 longer than the third and fourth. The abdomen is notably 

 more slender, and the lateral processes of the segments 

 extend more obliquely backwards ; the sixth segment is 

 nearly cylindrical, and the seventh, or middle plate of the 

 tail longer and much narrower, the terminal half being con- 

 siderably attenuated ; the upper surface has no distinct 

 furrow, as in TV. edidis, and there is on each side a small 

 spine, about the middle of its length, at the point where it 

 becomes narrower. The lateral plates of the tail partake 

 of the general tendency to attenuation, which so remark- 

 ably characterises the form of the species. 



Length nearly three inches. 



One specimen only of this species has come under my 

 notice, and for this I am indebted to Mr. Couch, who sent 

 it to me about five or six years since. It was taken on the 

 coast of Cornwall. I have much pleasure in dedicating so 

 interesting a species to a naturalist who has not only done 

 much for the local Fauna of his own district, but whose 

 observations on the habits and physiology of many forms of 

 marine animals are peculiarly valuable for their truthful- 

 ness and originality. 



That it is quite distinct from N. edtilis, the description I 

 have given above sufficiently proves : and it is equally so 

 from any of those, whether varieties or species, named by 

 Risso in his " Crustaces des Environs de Nice." The 

 characters given by this author are, unfortunately, so 

 vague, and the figures in the work just named so bad, that 

 it is frequently impossible to arrive at any tolerable cer- 

 tainty as to the identity of the species described by him, or 

 to ascertain whether the distinctions be specific or not. 



