EEPORT ON THE LAMELLIBRANCHIATA. 45 



Necera capensis, n. sp. {PI. IX. figs. 5-56). 



Testa tenuis, ovato-rostrata, iiifequilateralis, albida, epidermide tenuissima induta, 

 iiicrementi lineis striata, latere uutico subacute rotundato, postico anguste rostrato, 

 rostro circiter ^ longitudinis sequante. Margo dorsi anticus valde declivis, leviter 

 convexus, posticus longior, minus obliquus, concavus. Ventris margo regulariter 

 arcuatus, postice ad rostrum sinuatus. Umbones pauIo postmediani, leviter supra 

 marginera elevati. 



Like most species of Necera this is very thin and fragile. It has a rather long beak 

 behind, is somewhat acutely rounded in front, rather angular at the apex, and well 

 curved below. It is inequilateral owing to the length of the rostrate end, whitish, and 

 covered, more or less, with a thin but rougliish epidermis, which is less worn off the beak 

 than elsewhere. The front dorsal outline is slightly convex and considerably sloping, the 

 posterior being somewhat longer, less oblique, and gently concave. The sculpture 

 consists of fine concentric lines of growth, most conspicuous upon the beaks. The 

 <-artilage-pit is small, the lamellar lateral tooth of the right valve moderately long and 

 erect, and the scars and pallial line very indistinct. 



Length 15 mm., height 8, diameter 5. 



Habitat. — Station 142, off the Cape of Good Hope, at a depth of 150 fathoms ; green 

 sand. 



This, like several other species of the genus, is principally distinguished by its shape, 

 there being little of importance as regards sculpture, epidermis, and hinge to separate 

 it from certain allied forms. It differs from Netera rostrata, Spengler, in possessing a 

 shorter beak, and the ventral margin in front of the rostrum is longer and less arcuate. 

 In outline it more closely resembles Nccera hindsiana, A. Adams, from Japan, but differs 

 from it in having finer concentric sculpture and a more acute anterior end. 



Necera j^lciten.sis, n. sp. (PI. IX. figs. 4-46). 



Testa tenuis, albida, elongata, antice acute rotundata, postice sublonge rostrata, 

 mediocriter globosa, incrementi lineis striata, hand nitida. Margo dorsi anticus primo 

 rectiusculus, deinde obliquus, parum arcuatus, posticus elongatus, paulo declivis, subrecti- 

 linearis vel leviter concavus. Margo inferior late arcuatus, postice sub rostro sensim 

 sinuatus. Umbones leviusculi parum prominentes, paulo ante medium collocati. 

 Rostrum impressione radianti definitum, subabrupte truncatum. Valva dextra dente 

 laterali lamcUiforuie postico instructa. Fossa ligamenti valvte sinistra^ minuta, paulo 

 obliqua. Linea cardinis ante umbones leviter expansa. 



This species is very thin, ovate-rostrate, moderately convex, sharply rounded in front, 

 and ends behind in a rather long but not very slender beak. It is white, without 



