498 On some neio mid peculiar Mollusca. 



from the inside) slightly incurved on the posterior side : liinge- 

 plate thin, broader on the anterior side : teeth consisting of a 

 single lateral on the posterior side in the right valve ; this is 

 rather long, triangular, and erect : inside glossy : muscular 

 scar on the posterior side below the hinge-line triangular and 

 strongly marked, the other scars inconspicuous. L. 0'5. 

 B. 0-75. 



Station 12, 1450 fras. ; a valve and fragments. ^ Porcupine ' 

 Expedition, 1870, off the coast of Portugal, 994 fms. ; a small 

 valve. 



This differs from N. notahilis in shape and sculpture, as 

 well as in having only a single lateral tooth. An imperfect 

 valve represents a specimen an inch broad. The perfect valve 

 and portion of a larger one have been drilled by apparently 

 some small Siphonobranchiate mollusk. 



Necera papyria *, Jeffr. 



Shell oval, convex, exceedingly thin and fragile, serai- 

 transparent, rather glossy : scidpture, none on the umbones ; 

 from 15 to 20 concentric lamellar ridges on the body of the 

 shell, besides numerous and close-set but irregular minute 

 hair-like stride in the interstices of the ridges ; the rostral part 

 on the posterior side is closely striated across, and marked 

 lengthwise Avith three or four slight rib-like striai: colour 

 white : margins rounded on the anterior side and in front, 

 sloping towards the rostrum, which is snout-like and rounded 

 at its extremity, incurved and somewhat upturned behind : 

 heaks as in other species ; umbones prominent : cartilage and 

 pit or receptacle oblong, placed obliquely under the hinge-plate 

 on the posterior side of the beaks : hinge-line nearly straight, 

 but upturned on the posterior side : hinge-plate narrow and 

 slight : teeth^ none in the left valve ; the right valve is imper- 

 fect : inside glossy : scars inconspicuous. L. 0*2. B. 0"4. 



Station 12, 1450 fms. j two imperfect valves and a frag- 

 ment. 



Its delicate texture, the fewer number of ridges, and the in- 

 termediate striaj will serve to distinguish this from any known 

 species. 



Necera angularis\ , Jeffr. 



Shell inequivalve, obliquely oval, convex, thin, semi- 

 transparent, and glossy : sculpture 25-30 concentric lamellar 

 ridges on the body of the shell, besides numerous and close- 

 set but irregular microscopic hair-like intermediate strige ; the 



* Paper-like. f Having an angle. 



