CARDIOMORPHA. 257 



Cakdiohoepha, Miller, 1889. N. Amer. Geol. and Palaeont., p. 469. 



— ? Worthen, 1890. Geol. Surv. Illinois, vol. viii, p. 126. 



— Keyes, 1894. Missouri Geol. Surv., vol. v, pt. 2, Pal., p. 131. 

 Non — Beushausen, 1895. Abliand. Kon. Preus. Geol. Landes., Heft 17, 



Die Lamell. des Ebeinsch. Devon, p. 276. 

 Edmondia, Beushausen, 1895. Ibid., p. 287. 



Generic Characters. — Equivalve, inequilateral, gibbose, of obliquely rounded 

 or subquadrilateral shape. The umbones are swollen and elevated, with the 

 beaks markedly prosogyrous. Lunule absent. The hinge-plate is edentulous ; 

 the ligament small and external. The muscle-scars are shallow, and the pallial line 

 entire. Shell thin, either ornamented with fine regular concentric lines, or smooth. 



Observations. — This genus was erected by de Koniuck in 1842 for certain 

 shells which till that time had been confounded with Isocardia, but he included in 

 it shells which, in his subsequent works, he recognised as belonging to totally 

 different species. Out of thirteen species described he retained only one in the 

 genus in his latest work ; and, curiously enough, the type of the genus C. elongata, 

 a species founded on a single valve, is not mentioned in this latter work. As 

 this specimen, cannot be found, 0. oblonga becomes the type in its place; in fact, 

 de Koninck states that he regards this species as the type of the genus. This 

 species was figured and described by Sowerby (oj). cit.) under the name of 

 Isocardia. M'Coy, unaware of the erection of Cardiomorpha by de Koninck, 

 proposed the generic name Isoculia for these shells, but immediately substituted 

 de Koninck's name for it in the text of his book, though in some copies Isoculia 

 appears at the foot of the plates. He described four species, only two of which, 

 G. corrugata and C. ventricosa, were new ; but he included erroneously Schizodus 

 axiniformis, Phillips, sp. 



Lately Dr. Beushausen has criticised de Koninck's diagnosis of Gardiomorpha. 

 He demurs to the statement that a groove exists for the internal ligament, and in 

 this stricture I am in agreement with him ; but he further objects to the separa- 

 tion of Isoculia from Cardiomorjpha, stating that the absence of a lunule and the 

 deep concentric grooving, on which de Koninck relied as generic characters, are 

 found in certain Devonian shells which he describes. I do not think that these 

 characters supply sufficient grounds for separating Isoculia from Cardiomorjpha, 

 and am of opinion that no lunule exists in M'Coy's species. Indeed, I am of 

 opinion that most if not all the shells referred to Cardiomorjpha by Beushausen do 

 not belong to this genus, which was enlarged by that author to receive them ; nor 

 can I understand on what grounds he bases his statement that a lunule is present 

 in C. oblonga, or in any of the species included in the genus by de Koninck in his 

 later work. 



Many of Beushausen's Devonian species are transverse, and possess acute 



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