181 



genus Cythere, but in reality differing both from this genus and its allies by 

 several well-marked particularities. The generic name proposed alludes to the 

 peculiar gibbosity of the shell. 



83. Kyphocythere limicola (Norman). 



(PI. LXXXIl.) 



Cythere limicola, Norman, Nat. Hist. Trans. Northumb. & Durham, Vol. I, p. 20. 



PI. VI, figs. 1-4. 



Syn: Cythere nodosa, G. O. Sars. 

 areolata. Brady. 



Specific Characters. Female. Shell, seen laterally, subquadrangular in 

 shape, a little higher in front than behind, greatest height considerably exceeding 

 half the length, dorsal margin nearly straight in the middle, but gibbously 

 produced both in front and behind, ventral margin slightly sinuated in the 

 middle and curving evenly upwards behind, anterior extremity obliquely rounded 

 off, posterior obtuse or slightly angular in the middle; seen dorsally, irregularly 

 ovate or somewhat hexagonal in outline, with the greatest width behind and 

 slightly exceeding half the length, lateral edges angularly bent behind, anterior 

 extremity abruptly contracted, posterior triangular. Surface of shell very uneven, 

 each valve being provided dorsally, in front of the projecting supero posteal corner, 

 with 2 successive very conspicuous nodiform protuberances, and more ventrally 

 with a broad angular expansion continued in front as a well-marked ridge 

 curving upwards to the ocular region; central part of valves transversally 

 rugose; edges smooth and clothed in front and behind with scattered very fine 

 hairs. Anterior antennae with the terminal joint very narrow and fully as long 

 as the preceding joint. Posterior antennae with the apical claws gradually 

 increasing in length distally. Posterior extremity of body terminating in 2 

 juxtaposed setae. 



Male of rather smaller size than female, with the shell less high and the 

 dorsal margin slightly concaved. Copulative appendages of moderate size, 

 basal part irregularly rounded, terminal part produced in front to a very long 

 and thin lappet, behind to a short triangular corner. 



Colour of shell fuscous grey; limbs colourless. 



Length of adult female 0.65 mm. 



Remarks. This remarkable form was first described by Norman from 

 specimens collected off the eastern coast of England, and was subsequently 

 recorded by the present author under the name of Cythere nodosa. The peculiar 

 rugose and tuberculated surface of the shell and the absolute absence of eyes 



