1881.] NATURAL SCIENCES OP PHILADELPHIA. 423 



REMARKS ON THE MOLLUSCAN GENERA HIPPAGUS, VERTICORDIA 

 AND PECCHIOLIA. 



BY ANGELO HEILPRIN. 



The genus Hippagus was founded by Dr. Isaac Lea, in 1833 

 (Contributions to Geology, p. 72), for a small cordiform fossil 

 shell from the Eocene deposits of Alabama, whose external 

 appearance bore a somewhat general resemblance to Isocardia. 

 Its affinities with that genus were at the time pointed out by 

 that naturalist, who did not hesitate to class it in its immediate 

 neighborhood, despite the great diflerences that were presented 

 by the structure of the hinge in the two genera. To my 

 knowledge, onh' two species, one other than the American, are 

 as yet known to belong to this genus, the second one being a 

 species from the Arrialoor Cretaceous group of Stripermatiir, 

 India, discovered by the late C. Aemilius Oldham, and to which 

 Stoliczka has applied the specific name of Aemilianus (Palseonto- 

 logia Indica, Memoirs Greol. Surv. India, Cretaceous Fauna, iii, 

 p. 262). In 1846 Mr. Searles Wood published in the seventh 

 volume of Sowerby's Mineral Conchology, p. 6T, his diagnosis 

 of a new genus of fossil shell, for which he some years previously 

 proposed the name Verticordia, and which was intended to 

 embrace the only species known at the time, a fossil of the 

 English crag (the Gryptodon ? Verticordia of the " Catalogue of 

 the Crag Mollusca," Annals and Magazine of Natural History, 

 1840, vi, p. 24*7). Almost simultaneously with the discovery of 

 the Crag fossil, Philippi discovered in Calabria, South Ital}", a 

 very closely allied form, which, on the strength of the transcript 

 of the characters of Lea's genus, as given b}^ Bronn in the Lethsea 

 Geognostica, he referred to Hippagus (sp. acatlcoHtatus) (Enu- 

 meratio Molluscorum Sicilise, 1844, ii, p. 42). Probably guided 

 by the views of Philippi, Sowerby {loc. cit.) considered the new 

 genus of Wood as untenable, and accordingly referred the 

 English fossil in question likewise (although with doubt) to the 

 genus Hippagus^ imposing upon it the new specific name of 

 cardiiformis (Miu. Conch., vii, p. 68). Sowerb^^'s example, 

 singularly enough, is followed by Wood in his " Monograph of 

 the Crag Mollusca" (Palaeontographical Soc. Reports, ii, p. 149, 

 1851-3), who now renounces his genus, referring his species to 



