8 CRETACEOUS LAMELLIBRANCHIA. 
(d’Orbigny). For the relation of this to N. scapha (d’Orbigny) and N. phaseolina 
(Michelin), see pp. 4, 9. 
- Remarks.—Specimens referred to N. scapha (d’Orbigny) by Gardner (vide 
ante, p. 4), and stated to come from the Lower Greensand of Atherfield, 
probably belong to this species. One example is figured on PI. I, fig. 32. 
Types.—The types, and also the specimens figured by Gardner, are in the 
Bristol Museum. 
Distribution —Blackdown Greensand (zone x ); Greensand of Haldon (fide 
Downes); Grey Chalk of Dover (fide Gardner). 
Nucurana ancubata (Sowerby), 1824. Plate I, figs. 33 a—e, 34a, b, 35a—d. 
1824. Nucuna aneutata, J. de ©. Sowerby. Min. Conch., vol. v, p. 120, 
pl. eccelxxvi, fig. 5. 
1850. Lepa aneunara, A. d’Orbigny. Prodr. de Pal., vol. ii, p. 159. 
1854. — — J. Morris. Cat. Brit. Foss., ed. 2, p. 205. 
1866. — — F. J. Pictet and G. Campiche. Foss. du Terr. Crét. de 
Ste. Croix (Matér. Pal. Suisse, ser. 4), 
pt. 3, p. 401. 
1884. — —— J. S. Gardner. Quart. Journ. Geol. Soc., vol. xl, p. 188, 
pl. iv, figs. 17—19. 
Description.—Shell small, more or less oval or triangular, moderately convex ; 
somewhat rounded anteriorly, pointed posteriorly. Ventral margin regularly 
curved, but slightly sinuous posteriorly. Umbones prominent, incurved; a ridge 
extends from each umbo both anteriorly and posteriorly, limiting two depressed 
areas. Ornamentation consists of fine concentric ribs. Anterior and posterior 
portions of the hinge-line of nearly equal length; teeth narrow, elongate. 
Measurements : 
(1) @) (8) 
Length . : 55 : 5 : 4. mm. 
Height. ; 4 F a) ‘ Dinas 
Thickness ; 3 ; 3 7 22s 
(2) is one of Sowerby’s types. 
Affinities. —This species is similar to N. Marix (d’Orbigny), but is smaller, 
more conyex, with the posterior part of the shell usually less elongated, and 
the umbones more prominent. 
Types.—In the British Museum. The specimens figured by Gardner are in 
the Bristol Museum. 
Distribution.—Blackdown Greensand. 
