REPORT ON THE LAMELLIBRANCHIATA. 233 



This species has very much the form of Nucula dilatata, Philippi, a Sicilian 

 Tertiary fossil, but appears to be more solid, more strongly striated, and has a well- 

 marked doz'sal area, and the posterior dilated side is not so perpendicularly truncate. 



Leda inaudax, n. sp (PL XIX. figs. 4-4a). 



Testa minuta, couvexa, solida, triangulariter ovata, antice rodundata, postice euneata, 

 alba, concentrice tenuiter et regulariter lirata. Margo dorsi utrinque sequaliter valde 

 declivis, antice vix excurvatus, postice in medio leviter concavus. Margo inferior late 

 arcuatus, postice haud sinuatus. Umbones rotundati, paulo antemediani, incurvati, 

 postice iuclinati. Linea cardinis fortis, dentibus circiter octo utrinque instructa. 



Length 2^ mm., height If, diameter 1^. 



Habitat. — Station 24, ofi" Culebra Island, West Indies, in 390 fathoms ; Pteropod ooze. 



Although narrowed behind, this little shell has not a rostrate aspect, there being no 

 incurvation of the ventral outline near the posterior extremity which is roundly 

 pointed. Neither is there any radiating depression as in some allied forms, and the 

 concentric lir'se are fine and regular. 



Leda conftnis, n. sp. (PI. XIX. figs. 5-5a). 



Testa parva, solida, convexa, ovata, postice acuminata, breviter rostrata, impressionem 

 radiantem latam exhiliens. Valvae nitidse, flavescentes, incrementi lineis tenuissimis 

 striatse. Margo dorsi anticus declivis, arcuatus, posticus primo rectiusculus, obliquus, 

 dein magis descendens. Margo inferior late curvatus, prope extremitatem posticam haud 

 profunde sinuatus. Umbones subpellucidi, postice inclinati. Dentes fortes circiter 

 18-20 linea cardinali forti dispositi. 



Length 3g mm., height 2^, diameter If. 



Habitat. — Station 78, off the Azores, in 1000 fathoms ; volcanic mud. 



This species bears considerable resemblance to Leda messanensis, but does not attain 

 so large a size. It is proportionally thicker,* more convex, more inequilateral, the 

 posterior end being considerably smaller than the anterior, which is rather less acutely 

 rounded. 



Leda solidula, n. sp. (PI. XIX. figs. G-Ga). 



Testa subtriangulariter ovata, postice acute sed breviter rostrata, solida, convexi- 

 uscula, sequilateralis, nitida, albida, concentrice subfortiter lirata, liris utrinque attenuatis 



(ZOOL. CHALL. EXP. — PART XXXV. — 1885.) Mm 30 



