CYPRICARDELLA ANN^E. 355 



are only varietal, or due to small differences of growth only, and indeed 

 de Koninck's descriptions of all these species are practically identical. He has 

 correctly recognised that the Gypricardia rlwmbea of Young and Armstrong is not 

 the G. rhombea of Phillips, but referred it to T. prsesectum of de Ryckholt. 



I have been able fortunately to meet with shells showing the hinge and internal 

 characters most perfectly preserved, and therefore have sufficient grounds for 

 placing the species under Cypricardella rather than under Sanguinolites ; but the 

 external form, and above all the peculiar everted margin of the escutcheon, show 

 more affinity to the former than to the latter genus. 



Opkicardella annj5, de Ryckholt, sp., 1853. Plate XXXIX, figs. 31 — 35. 



? Nucula carinata, IP Coy, 1844. Synops. Carb. Foss. Ireland, p. 68, pi. xi, fig. 21. 

 ? Trapezium annje, de Ryckholt, 1852. Melanges paleontol., p. 131, pi. xiv, figs. 



21, 22. 

 ? Leda carinata, Morris, 1851. Cat. Brifc. Foss., 2nd edit., p. 205. 

 Ctenodonta carinata, Bigsby, 1877. Thesaurus Devonico-Carboniferus, p. 303. 

 Sanguinolites ann.e, de Koninck, 1885. Ann. Mus. d'Hist. Nat. de Belgique, 



torn, xi, p. 65, pi. xvii, figs. 11, 12. 



Specific Characters. — Shell small, oblique, nearly regularly diamond-shaped, 

 inequilateral, strongly carinate. The anterior end is short, narrow, and almost 

 obsolete, its border rounded. The inferior margin is straight, depressed, and 

 comparatively short, meeting the posterior border at a wide obtuse angle. The 

 posterior border is obliquely truncate from above downwards and forwards, almost 

 straight, and about as long as the inferior border. The hinge-line is very long, 

 arched in front, slightly curved, produced, depressed posteriorly, meeting the 

 posterior border at a well-marked acute angle. The umbones are small, obtuse, 

 twisted forwards, not elevated, and placed very far forwards. Passing downwards 

 and obliquely backwards from the umbones to the postero-inferior angle is a well- 

 marked obtuse keel, which divides the valve into two almost equal triangular 

 portions : the lower and anterior is gently swollen ; the upper and posterior is 

 compressed and somewhat concave, forming an expanded dorsal slope. Lunule 

 and escutcheon well marked. The latter is wide and deep, its edges angular. 



Interior. — The anterior adductor muscle-scar is small, rounded, situated 

 immediately within the antero-superior angle, and is marked off from the rest of 

 the valve below and behind by a well-marked ridge. The posterior muscle-scar is 

 larger, and is placed just within the postero-superior angle. The pallial line is 

 simple. The hinge appears to have a thin elongate posterior lateral tooth, but the 

 anterior part has not yet been isolated. 



