496 Dr. J. Gwyn Jeffreys on 



is quite distinct from any of the allied species described and 

 figured by Mr. Hinds in the ' Zoology of the Voyage of the 

 * Sulphur,' ' and from those described by him in the ' Proceed- 

 ings of the Zoological Society ' for 1843. 



Some of the ' Valorous ' fragments indicate a size of half an 

 inch in length by three quarters of an inch in breadth. 



A fragment of another species of Necera occurred at Station 

 13, in 690 fathoms. It represents a specimen apparently 

 nearly an inch broad and more than half an inch long. It has 

 a rather compressed shape, is strongly wrinkled concentrically, 

 and the rostral extremity is defined by two keels. The inden- 

 tation below the rostrum is well marked. It probably belongs 

 to a species which I dredged in the ' Porcupine ' Expedition 

 of 1870, off the coast of Portugal, at depths of from 740 to 

 1095 fathoms, and which I propose to name hicarinata. 



I have also an undetermined fragment (part of the hinge of 

 a right valve) of another smooth species from Station 12, 

 1450 fathoms, which shows a large cartilage-pit and an elon- 

 gated triangular lateral tooth. 



Necera exigua^ ^ Jeffr. 



Shell oval, globose, thin, semitransparent, and glossy : 

 scul^oture^ none except in front, where are some slight and 

 close-set concentric striae : colour whitish : margins gently 

 curved in front, rounded on the anterior side, incurved behind 

 on the posterior side, with a short and abrupt beak-like ex- 

 tremity on that sidcj which has scarcely any indentation below : 

 heaks very small and maraillar, incurved towards the anterior 

 side ; umbones prominent, and projecting behind : carti- 

 lage and pit small, triangular : liinge-line slightly rounded on 

 the anterior, and incurved on the posterior side : hinge-plate 

 slight, folded back on the anterior side : teeth, a rather short 

 triangular lateral on the posterior side of the right valve : 

 inside glossy and stippled, showing under the microscope 

 traces of longitudinal striae: scars inconspicuous. L. 0"125. 

 B. 0'2. 



Station 12, 1450 fms. ; a few valves and fragments. 



This species differs from the young of N. ohesa, Lovdn, in 

 being more convex and proportionally shorter, the front margin 

 is more rounded, the rostral point is more abrupt, the ventral 

 sinus (or indentation on the lower side of the rostrum) is 

 scarcely perceptible, and the dorsal slope is more curved. N. 

 suhforta, G. O. Sars, MS., from Norway and Spitzbergen, is 

 shorter and twisted. 



* Small. 



