TRANSACTIONS OF WAGNER 

 1328 



TERTIARY FAUN'A OF FLORIDA 



Venererupes Swainson, Elem. Mod. Conch., 1835, fide Agassiz. 



Venererupis Sowerby, Conch. Man., p. 113, 1839; Verany, Cat. Gen., p. 13, 1846. 



Venerupes Swainson, Malac., p. 376, 1840. 



Pullastra (sp.) Sowerby, Gen. Shells, fasc. xxviii., June, 1826. 



Rupellaria H. and A. Adams, Gen. Rec. Moll., ii., p. 437, 1857 (not of Fleuriau). 



Venerupis Stoliczka, Cret. Pel. India, p. 141, 1871 ; Fischer, Man. de Conchyl., p. 1087, 



1887; Dautzenberg, Moll, de Roussillon, ii., p. 438, 1893. 

 fPetrifora Latreille, Nat. Fam. Thierr., p. 211, 1827 (no type mentioned). 

 Irus Herrmannsen, Ind. Gen. Mai., ii., p. 684 ; not of Oken, Lehrb. der Naturg., pp. 230, 



848, 1815. 



This genus was, naturally enough, at first confounded, even by Lamarck, 

 with nestlers of other genera. Sowerby proposed to unite the species of Vene- 

 rupis and the group named Tapes by Megerle von Miihlfeld in one genus, 

 substituting the name Pullastra for that given by Lamarck on the ground that 

 the latter would be inappropriate for the combination. Oken in 1815 proposed 

 a genus Irus for three species of bivalves mentioned by Poli, but in his Index 

 he refers one of them to Pandora and another to Petricola, leaving only one 

 to represent his genus, the Tellina rhomboides of Poli, or Irus rugosus of Oken, 

 which is a synonym of Saxicava arctica. The genus Irus Oken is therefore 

 an exact synonym of Saxicava. 



The genus has long siphons, with papillose orifices, united for about half 

 their length. The foot is grooved and byssiferous. The valves are moder- 

 ately elongate and subquadrate. The sculpture is radial with prominent rather 

 distant concentric lamellation. There is no lunule, and an area bounded by a 

 keel, in the left valve only, represents what may be called the escutcheon. The 

 ligament is exposed ; the pallial sinus short, ascending, free, and blunt in front ; 

 the internal margins are smooth in the type. The nepionic shell is polished and 

 colored, the adult dull and rude. The dental formula is L - IOIOI :. The anterior 



R. 010101. 



right and posterior left cardinals are entire and slender, the others broad and 

 deeply bifid. The species of the group are nestlers in rock cavities, by reason 

 of which they are frequently deformed and abnormal. They have been much 

 confused with the species of Petricolida, which have in the adult condition a 

 different dental formula. 



Venerupis lamellifera Conrad is reported by Cooper from the Californian 

 Pliocene (under the name of Rupellaria lamellifera) and from the Quaternary 

 beds of the coast. A thorough revision of the Californian Tertiary bivalves is 

 likely to reveal other species in their later beds. The genus does not occur on 

 the Atlantic coast of North America. 



