199 



Remarks. The above-described species is closely allied to C.Jonesi, but 

 of somewhat larger size and moreover easily distinguished by the numerous 

 scale-like prominences on the lateral faces of the valves, as also by the muc- 

 ronated shape of the spine attached to the infero-posteal corner and of that 

 terminating the lateral expansions of the valves. 



Occurrence. The only place where I have met with this form is at Skraa- 

 ven, Lofoten islands. It was found here occasionally in the considerable depth 

 of 200300 fathoms, muddy bottom. Norman has however taken it also at 

 Stoksund, west coast of Norway. 



Distribution. Shetland. 



Fossil. Belgium. 



Subfam. 4. Cytherurinae. 



Remarks. This subfamily has been proposed by G. W. Muller, but I do 

 not find that its real extent is clearly defined. As far as I understand, it is 

 taken by that author in a very wide sense. In the present account this sub- 

 family is restricted to comprise a number of very small Cytheridae,. chiefly 

 referable to the genus Cytherura, G. O. Sars. The subfamily is well distinguished 

 from the 3 preceding ones, both as to the shell and to the structure of the limbs. 



Gen. 42. Cytherura, G. O. Sars, 1865. 



Generic Characters. Shell, as a rule, comparatively thin, only slightly 

 calcareous, terminating behind in a more or less sharply defined obtuse protu- 

 berance, surface smooth or slightly reticulated, often with longitudinal folds, 

 which in some cases are elevated to sharp keels. Hinge imperfectly developed. 

 Eyes distinctly separated. Anterior antennae rather feeble, with the terminal 

 part gradually attenuated, 4-articulate, and clothed in front with scattered com- 

 paratively short setae. Posterior antennae with the penultimate joint distinctly 

 subdivided, apical claws short, flagellum well deweloped in both sexes. Mandibles 

 very strong, with the cutting teeth blunt and more or less' reduced in number, 

 palp 4-articulate, with none of the setae particularly prolonged, vibratory plate 

 very small, with only a single distinctly developed seta. Maxillae with both the 

 palp and the masticatory lobes narrowly produced, the 2 lowermost of the setae 

 bordering the vibratory plate quite nacked and turned downwards. Legs not 



