58 CRETACEOUS LAMELLIBRANCHIA. 
Non 1842. Cucunn#a @uasra, P. Matheron. Catal. méthod. et descript. des Corps foss. 
du Bouches-du-Rhone, p. 161. 
— 1843. — — 4H. B. Geinitz. Die Verstein. von Keislingswalda, 
p. 14, pl. iii, figs. 4—7. 
?— 1846. Arca (Cucunn#a) ataBra, A. FE. Reuss. Die Verstein. der bohm. Kreide- 
format., pt. 2, p. 18, pl. xxxiv, fig. 44; pl. 
xxxv, figs. 1, 2. 
— 1847. —  Guapra, J. Miller. Petref. der Aachen. Kriedeformat., pt. 1, p. 18. 
— 1847, Cucunima evapra, Miller. Ibid., p. 19. 
— 1858. Arca rrBrosa, J. Vilanova y Piera. Mem. geog.-agric. de Castillon, 
pl. ii, fig. 13. 
?— 1863. CucuLtma anaBra, R. Drescher. Zeit. d. deutsch. geol. Gesellsch., vol. xv, 
p. 349. 
?— 1875. Anca etapra, H. B. Geinitz. Das Elbthalgeb. in Sachsen (Paleonto- 
graphica, vol. xx), pt. 1, p. 221, pl. xlix, figs. 1, 3. 
?— 1881. — _ Frprosa, J. Kiesow. Schrift. d. nat. Gesellsch. Danzig, N. F., vol. v, 
p. 410. 
?— 1885. Cucunrnma cGuaBra, F. Nétling. Die Fauna der baltisch. Cenoman- 
geschiebe (Palwont. Abhandl., vol. ii), p. 25. 
P— 1897. — (Iponvarca) @naBRa, R. Leonhard. Die Fauna der Kreide- 
format. in Oberschlesien. (Paleonto- 
graphica, vol. xliv), pp. 21, 51. 
Deseription.—Shell subrhomboidal or more or less oval, a little inequilateral 
and oblique; high, convex. Anterior margin curved, passing gradually into the 
ventral margin, and joining the hinge-line at a slightly obtuse angle. Posterior 
margin nearly straight, oblique, forming with the hinge-line an obtuse angle, and 
with the ventral margin an acute angle more or less rounded. Umbones large, 
with a rounded but usually well-marked carina extending from each to the 
postero-ventral angle of the valves. Sometimes a thread-like ridge, crenulated, 
passes from the umbo of the right valve to the middle of the posterior margin. 
Hinge-area long, but com paratively narrow ; with three or four, sometimes 
more, ligament-grooves on each side. Ornamentation consists of numerous radial 
ribs, sometimes raised and somewhat granular, crossed by concentric growth-lines. 
Hinge-line long, with from five to eight central transverse teeth, and three or four 
long lateral teeth, placed parallel or nearly parallel to the hinge-line, and striated. 
Posterior adductor plate large. Anterior adductor impression smaller. Margins 
of valves entire. 
Measurements: 
@ @2 ©& ©® (5) (6) = (7) 
Length . F : ~ eh ey 4 0) SX 22 21 mm. 
Height . 5 ‘ 61 Voll) 743525 30%o 2 ail 
Thickness j ; . 62 46 40 28 31 PL UG 
Hinge-line ‘ . 60 44 35 27 2025 7a Ge ess 
Ajinities—The forms described by Sowerby under the names Cucullea glabra 
