398 CEETACEOUS PELECYPODA 



however, the genus from all OSTRUA CJEA, and as there is an anterior muscular 

 scar indicated in most of the MYTILA CJEA, the classification of the genus may be 

 more correct in this place. If this should not be the case, the only other classifica- 

 tion admissible would be near Myochama (see p. 60) in the Anatinidm (sub-family 



PANDORIN^J, 



30. Vulsella^ Lam., 1799. Sub-equivalve, moderately tumid and solid, higher 

 than long, and sometimes ventrally gaping at the edges, with pointed or incurved 

 more or less approached beaks, which contain internally the ligamental pit, its 

 margins being generally considerably thickened on both sides ; muscular scar sub- 

 central, faint above, more marked at its lower edge ; outer surface fibro-lamellar, 

 finely scabrous or radiately ribbed; type, V. lingulata, Linn. A list of the eighteen 

 recent and about eight tertiary species is given by Munier-Chalmas (Bull. Soc, 

 Normandie, viii, p. 102, et seq.). Species from mesozoic and older deposits are 

 doubtful. 



31. Malleus, Lam., 1799. Sub-equivalve, narrowly elongated, and often 

 twisted ; hinge area long, internally thickened, with distant beaks, more or less pro- 

 duced on either side into a long narrowed wing, ligamental pit extending somewhat 

 internally, a byssal sinus in front and very close to it ; muscular scar somewhat 

 irregularly elongated, placed some distance from the cartilage pit ; type, M. vulgaris, 

 Linn. Reeve (Iconica, xi,) refers thirteen species to this genus. No fossil species 

 are known with suflS.cient certainty. 



List of ceetaceous species of Aviculidje. 

 a. AVIGVLINJE, (vide genas Avieula, in Pictet's Mat. Pal. Suiss., V"^^ ser., 4^^^ part., p. 70. 

 I.— 'A. valangiensis, P. and C. ; in form closely resembling Actinodesma, Sandb., but appa- 

 rently without any of the peculiar hinge-ribs which characterize this genus. 

 2-3. — A. Carteroni SLnd CoUaldina, d'Oih, 



^.—A. Sowerhi/ana, Math., belongs to the sub-genus Meleagrina, 



b,—A. Cornueliana, d'Orb., ( = sudradiata, Desh.,) is an Oi^^toma, a sub-genus of Fseudo- 

 monotis. 



6-8.— J. Neocomiensis, Cott., and Sanctce-crucis, Pict. and Camp., VLndi pectinata, Sow. 



9.— J. sub-depressa, d'Orb., f= depressa, Forb.,) closely resembles A. anomala, both of which 

 have the external shape of recent Crenatulm, 



10-14.— J. aptiensis, BauUniana, sub-plicata, Cenomaniensis and intermpta, d'Orb. 



15-16.~-J. anomala,"^ Sow., and Eolis, d^Orb., have, as already noticed, the form of some 

 recent Orenatulm. 



17. — A, Moutoniana^ d^Orb. 



18.—^. grypJimoides, Sow., is most likely an Aucella, 



19.—^. simulaU, Baily, belongs to Oxytoma, a sub-genus of Pseudomonotis. 



20-22.—^. Nysa and Perigordina, d^Orb., Carentonensis, Coq., are not sufficiently well known; 

 the last may be an Oxytoma, judging from the depressed form of its valves. 



23.— J. glabra, Eeuss, is certainly quite a distinct species from A. anomala, 



U.-A. Neptuni, Goldf. I would be more inclined to regard this species as a Modiola than 

 an Avieula, but I have no specimens to compare. 



* Mem. Acad. Belgique, xxxiv, 1870, Briart et Cornet, Fossiles de la meule de Bracquegnies, p. 52. 



