236 THE VOYAGE OF H.M.S. CHALLENGER. 



The young shells obtained by the Challenger are not so pointed l^ehind as adult 

 specimens, and the area between the posterior radiating keels is much smoother and 

 the carinae themselves are not notched. The concentric strise in this species are coarser 

 near the umbones, on the hinder side of which, in a slight depression, they are somewhat 

 flexuose. 



Leda inopinata, n. sp. (PI. XIX. figs. 9— 9a). 



Testa parva, ovata, convexiuscula, postice brevissime rostrata, fere sequilateralis, 

 radiatim tenuiter lii-ata, lineis incrementi sculpta, albida ; margo dorsi utrinque leAdter 

 arcuata, parum declivis ; margo inferior late curvatus, prope extremitatem posticam 

 sinuatus. Cardo validus, dentibus denis utrinque munitus. 



This little species is ovate, rounded in front, and shortly beaked behind. It is 

 whitish, equilateral, moderately convex, and sculptured with numerous, slender, radiat- 

 ing lirse, some of which bifurcate towards the lower margin. They do not extend to 

 the beaked end of the valves, but are there replaced by a number of fine, irregular 

 wrinkles. The whole surface exhibits fine lines of growth, some of them being particu- 

 lai'ly well marked. From the umbones a distinct ridge extends to the extremity of the 

 short rostrum, in front of which the valves are depressed, so that the broadly curved 

 ventral outline is shaUowly sinuated at this point. The dorsal margin is only slightly 

 convex on each side, and very gently sloping, and the umbones are smooth at the tip, 

 small, central, and not much produced. The hinge is rather strong, and bears on each 

 side ten long, acute teeth. The cartilage -pit is broad and triangular. 



Length 3f mm., height 2\, diameter 2. 



Habitat. — Station 164, ofi" Sydney, Australia, in 950 fathoms ; green mud. 



This is unlike any species of the genus with which I am acquainted, and remai'kable 

 for the radiating lirae which cover the surface 



Leda micans, Adams. 



Leda micarw {Ada,ms MSS.), Hanley, in Sowerby's Thes. Conch., vol iii. p. 130, pi. ccxxix. fig. 100. 

 Lceda micans, Sowerby, Conch. Icon., vol. xviii. pi. vi. fig. 39. 



Habitat — Ofi" Le%'Tika, Fiji Islands in 12 fathoms. 



New Zealand is the only locality hitherto assigned to this species, and that has not 

 since been confirmed by Hutton {vide Manual New Zeal. Moll., p. 165). 



