A CRETACEOUS LAMELLIBRANCHIA. 
1881. Youpra (Nucuna) scapna, K. A. Zittel. Handb. d. Paleont., vol. ii, p. 54. 
84. Lupa scapua, J. S. Gardner. Quart. Journ. Geol. Soe., vol. xl, p. 188 
(partim), pl. v, fig. 23 ? (mon 21, 22). 
1884. — sparuubara, Gardner. Ibid., p. 139 (partim), pl. v, figs. 31—34. 
? 1884. —  scapna, O. Weerti, Die Fauna des Neocom. im Teutoberg. Walde 
(Paleont. Abhandl., vol. ii), p. 46. 
P 1898. — = ? A. J. Jukes-Browne. Geol. Mag., dec. 4, vol. v, p. 29. 
Non 1867. — (Nucuna) scapna, O. Fraas. Aus dem Orient, pt. i, p. 92. 
Description.—Shell elongate, oval, compressed, a little inequilateral; ventral 
margin nearly parallel to the dorsal; rounded anteriorly, tapering slightly and 
more compressed and pointed posteriorly. Postero-dorsal margin concave ; antero- 
dorsal straight or slightly convex. Lunule linear. Surface ornamented, except 
near the anterior and posterior ends, with fine concentric strie. 
Measurements : 
(1) (2) (3) 
Length : 15 15 ; 3 9 mm. 
Height Coe: Ooi : os 45 
Affinities —The form of the shell in this species is similar to that of N. lineata 
(Sowerby), but it is more compressed and generally larger; the ornamentation 
also is much finer. 
N. scapha differs from N. Marie (d’Orbigny) in being relatively longer, less 
convex, and less pointed posteriorly. It appears to differ from N. scaphoides 
(Pictet and Campiche) in its greater relative length, in having the postero-dorsal 
margin less concave, in the finer ornamentation, and its smaller size. 
The form of the shell in N. scapha is suggestive of the genus Yoldia, to 
which it was referred by Stoliczka.1 I am unable to give a definite opinion on 
this point, since the specimens which I have examined do not show the interior of 
the shell. 
Remarks.—Some of the examples considered by Gardner (pl. v, figs. 31—34) 
to be Leda spathulata, Forbes, certainly belong to this species. 
Specimens in the British Museum (Gardner Collection, No. L5109), from 
Atherfield, were referred to N. scapha by Gardner (pl. v, figs. 21, 22, vide supra), 
but are more convex than that species, and probably belong to N. lineata (Sowerby) 
(see p. 8). 
T'ypes.—l have not seen the type; it is not preserved in the d’Orbigny 
Collection at Paris. Of the specimens figured by Gardner as Leda scapha, the 
original of his figs. 21 and 22 is preserved in the British Museum; the original of 
fig. 23 is stated to be in the Woodwardian Museum, but is now missing. Of 
the examples figured by the same author as Leda spathulata, the original of fig. 32 
) 
1 « Paleont. Indica,” ‘Cret, Fauna S. India,’ vol. iii (1871), p. 324. 
