112 EOCENE MOLLUSCA. 



Fig. 3 in ' Min. Conch.' is more angulated than fig. 4, but I think they both belong 

 to the same species, as there is considerable variation in the outline among Mr. Wetherell's 

 specimens. 



7. N. curvata, Edwards, MS. Tab. XVIII, fig. 12, a, b. 



Spec. Char. N. testa transversa, ovato-subtrigonuld, tumidiusctdd, crassiusculd, obsolete 

 radiatd, radiis vel striis tenuissimis ; valde inaquilaterali ; pedi-regione angulatd, productd ; 

 ano-regione brevi, in medio prominenti ; margine dorsali sub-recta ; margine ventrali con- 

 vexiusculd ; lunula lanceolatd vix conspicud ; marginibus crenulatis. 



Shell transverse, ovately trigonular, slightly tumid, and moderately thick ; obsoletely 

 radiated with very fine lines or striae ; pedal region produced and angulated ; anal region 

 short, and rather prominent in the centre ; dorsal margin nearly straight, ventral margin 

 curved; lunule scarcely conspicuous, margins crenulated. 



Length, fths of an inch. 



Locality. Clarendon {Edwards). 



This species is at present very rare. It somewhat resembles N. sphenoides, but it 

 is comparatively longer ; it is more produced and angular at the pedilateral margin, and 

 it is less tumid than the Upper Eocene shell. 



Two or three specimens in Mr. Prestwich's cabinet, obtained from a boring for an 

 Artesian well at Southampton, appear to belong to this species ; the age of the bed from 

 which they came is not stated. 



8. Nucula Dixon i, Edwards, MS. Tab. XVIII, fig. 7, a—c. 



Nucula similis. J. Sow., in Dixon's Geol. of Suss., p. 93, t. 2, fig. 7, 1850. 



Spec. Char. N. testa ovato-subtrigonuld, turgidd, laevigata, valde inaquilaterali, 

 convexd ; siphoni-regione truncatd ; lunula obtuse angulatd vix perspicud ; car dine crassd, 

 dentibus magnis ; fossuld connexus elongatd ; marginibus crenulatis. 



Shell ovately triangular, somewhat tumid, smooth, convex, very inequilateral ; siphonal 

 region truncated ; lunule and corselet not very distinctly defined ; teeth thick and broad 

 towards the connector, margins crenulated. 



Length, jths of an inch ; height, |^ths of an inch. 



Localities. Bracklesham, Stubbington, Whitecliff Bay {Edwards). 



This species is by no means rare at Bracklesham. It appears to differ from similis in 

 being more tumid and less angular, and rather more elongated, and it has not the projecting 

 pointedness at the basal margin of the siphonal region which is characteristic of that species. 

 The exterior is more convex, and the radiating lines are less distinct in this than they are 



