CYTHERURA. 193 



straight. Outline, seen from above, ovate, widest in the middle, width equalling half the 

 length. End-view ovate, tumid, widest towards the base, width and height equal. Shell 

 smooth, obscurely reticulated. Very similar to the preceding, but larger, more ventricose, 

 and less distinctly beaked posteriorly. 

 Length, s^rd of an inch. 



Distribution. Recent. — Norway, Great Britain, Holland, Spitzbergen. 



Fossil. — Scotland : Duntroon, Loch Gilp, Kyles of Bute, Kilchattan, Cumbrae, Dum- 

 barton, Cartsdyke, Dalmuir, Barrie. Ireland: New Docks at Belfast, Portrush. 

 Norway, 



3. Cytherura flavescens, Brady. Plate XVI, figs. 7, 8. 



.1869. Cytherura flavescens, Brady. Ann. Mag. N. H., ser. 4, vol. iii, p. 49, 



pi. viii, figs. 13 — 15. 



Carapace, seen from the side, subquadrangular, nearly equal in height throughout, 

 height equal to half the length ; anterior extremity imperfectly rounded and somewhat 

 oblique ; posterior produced in the middle into a broad rounded beak ; superior margin 

 flattened, slightly sinuated in the middle ; inferior with a distinct median sinuation. 

 Seen from above, ovate, widest near the middle, subacuminate in front, mucronate 

 behind, width rather less than the height. Surface of the shell marked longitudinally 

 with numerous flexuous, anastomosing, but not very prominent, ribs. 

 Length, ^nd of an inch. 



Distribution. Recent. — Britain, Holland. 



Fossil. — Scotland : Kyles of Bute. 



4. Cytherura pumila, nov. sp. Plate XI, figs. 33 — 35. 



Carapace of i\vQ female, seen from the side, subovate, highest in the middle, height 

 equal to more than half the length ; rounded in front, produced in the middle behind, 

 but not beaked ; superior margin arched ; inferior nearly straight. Outline, seen from 

 above, compressed, ovate, widest near the middle, nearly thrice as long as broad, 

 extremities pointed. Shell of the male (fig. 35) long and narrow. Surface of the valves 

 obscurely undulated and finely punctate. 

 Length, -^th of an inch. 



Distribution. Recent. — Shetland. Gulf of St. Lawrence. 



Fossil. — Scotland : Duntroon, Cartsdyke, Dalmuir. 



25 



