MALAPTERA. 101 
Genus—Mataprera, Piette. 
Shell thin, fusiform or ovoid, wing very large, multidigitate, palmate, investing, 
bent back, extended on the columellar side, and sometimes on the posterior portion of the 
spire ; anterior canal placed upon an expansion which forms part of the wing, and 
consisting of a wide furrow bent backwards as in Aporrhais.”—FiscuEr. 
Such a genus as this possesses more resemblance to the existing Aporrhais than 
the average Jurassic Alaria does. Indeed, Cossmann (‘ Htage Bathonien,’ p. 71) 
regards Malaptera as merely a subgenus of Aporrhais. Most of these shells were 
formerly referred to Pterocera, Lamarck. 
20. MaLapTera BENTLEYI, Morris and Lycett, 1851. Plate ILI, figs. 1 a, 1b, Le. 
1851. Prerocera Bentunyi, Morris and Lycett. Great Ool.-Moll., p. 15, pl. in, 
figs. 15, 15a, 
1854. — -- — Morris, Catalogue, p. 274. 
Cf. also Cuenopus Pricravriensis, D’Orbigny. Piette, Cont. de la Pal. Franc., 
pl. xiv, fig. 9, and pl. xix, figs. 
10 aud 11. 
Bibliography, §c.—This is an Inferior-Oolite species described by Morris and 
Lycett as from the Great Oolite; but no similar form is known in the Great 
Oolite of this country. 
Description : 
Length of a full-sized specimen . : . 32mm. 
Ratio of width to length ‘ ‘ . 46: 100. 
Spiral angle : oy On 
Shell turrited, spiral angle rather convex, apex Pplant Whorls angular and 
tumid; posterior third of each whorl marked with very fine spiral lines, for the 
most part scarcely visible ; the anterior two-thirds carries four strong spiral lines. 
Body-whorl moderately large, and nearly equal to the length of the spire. It is 
ornamented by six strong spirals, from which the digitations of the wing arise. The 
wing embraces a very considerable portion of the spire. The posterior digitations 
are the strongest and also the widest apart, the first one being bent upwards, so as 
to form an angle of about 10° with the axis of the spire and nearly straight ; the 
three anterior digitations are less strong, and project much less farther from the 
edge of the palmated portion of the wing; they are bent downwards in an 
