434 Dr. J. Gwyn Jeffreys on 



neath the beaks : hinge-line straight : hinge-plate narrow, occu- 

 pying about one-fifth of the circumference of the shell : teeth 

 rather slight, slanting inwards, 4 or 5 on each side of the beak : 

 inside porcellaneous, with a bevelled and smooth or plain but 

 narrow edge : scars inconspicuous. L. 0*35. B. 0*3. 



Station 12, 1450 fms. 



Smaller and thinner than L. aurita^ and more delicately 

 sculptured ; the epidermis is not pilous as in that species, but 

 arranged in distinct rows ; the hinge-line is straighter, the 

 hinge-plate is narrower, and the teeth are much slighter and 

 set obliquely on both sides of the beak. In L. aurita the 

 teeth are erect on the anterior side, and slant inwards on the 

 posterior side. 



Limopsis cristata*, Jeffr. 



Shell rounded, but inclined to become oblique in aged spe- 

 cimens (as in Pectunculus glycymeris) ^ convex, rather solid, 

 opaque, rather glossy: sculpture, numerous fine riblets or raised 

 lines, which radiate from the beak, and equally fine concentric 

 lines, causing by their intersection a slight cancellation ; the 

 concentric lines are not granulated or beaded : colour white : 

 epidermis light yellowish-brown, arranged in regular spinous 

 rows, except towards the front, where it is somewhat matted 

 and projects beyond the edge of the shell : margins nearly 

 straight at the back, and rounded at the sides and in front : 

 heahs small, rather prominent, blunt, and incurved : hinge-area 

 long, reddish brown, smooth : cartilage horn-colour, placed in 

 a triangular cavity under the beaks : hinge-line gently curved : 

 hinge-plate broad, occupying about one-fourth of the circum- 

 ference of the shell : teeth small but strong, straightish, vary- 

 ing in number from 5 to 8 on each side : inside glossy, in- 

 distinctly striated lengthwise, furnished with a close- set row 

 of small tubercles a little within the edge of the shell ; these 

 tubercles are nearly equal in size : scars conspicuous. L. 0*25. 

 B. 0-25. 



Station 13, 690 fms. ' Porcupine ' Exp., 1869, off the 

 north-western coast of Ireland, 420-808 fms. ; Bay of Biscay, 

 517 fms. ; North Sea, 542 fms. : 1870, Bay of Biscay, 292- 

 1095 fms. 



It is distinguishable from L. minuta {horealis, Woodward) 

 by its shape and sculpture, its coarser epidermis (which in 

 L. minuta is much finer and greater in quantity), its teeth 

 being upright on both sides, instead of being oblique on the 

 posterior side, and by the marginal tubercles being equal in 

 size throughout and not larger on that side. Having, since 



* Crested. 



