730 CLASS XII. 



Comp. LAMARCK Ann. du Museum, in. pp. 25 31, PI. 2. 



Sp. Crenatula avicularis LAM. 1. 1. PI. 2, figs, r, 2, Cuv. R. Ani., id. ill., 

 Moll. PI. 8 1, fig. 2; in the seas surrounding the South American coasts. 



Vulsella LAM. Shell irregular, elongate, thin, subequivalve, 

 free. Hinge in both valves furnished with a tubercle cut out 

 with a conical pit for receiving the ligament. 



Sp. Vulsella linguatula LAM., My a vulsella L., KUMPH. Ami. Rariteitlc. Tab. 



46, fig. A, BLAINV. Malacol. PI. 62, fig. 5, from the Indian ocean, &c. 

 Some species are met with amongst corals, others in sponges. One 

 species from the tertiary formation is known ( Vulsella deperdita LAM. ; from 

 the calcaire grossier), and a few from the chalk-period. 



Malleus LAM. Shell subequivalve, rude, often undulate, de- 

 formed, elongate, flattened, auriculate, emarginate anteriorly for the 

 passage of byssus. Straight, triangular, sinus between the two 

 valves; points small, divaricate. Hinge edentulous; cardinal 

 fossula oblongo-conical, receiving the ligament. 



Sp. Malleus vulgaris LAM., Ostrea malleus L., KUMPH. Anib. RariteitTc. Tab. 



47, fig. II.; D'ARGENVILLE Conchyliologie, 1757, 4to, PI. 19, fig. A, 

 BLAINV. Malac. PI. 63, fig. 4; this shell, commonly called the Polish 

 Hammer, is found in the East-Indian Ocean. On account of its rarity in 

 collections, Malleus albus LAM., CHEMNITZ Conchyl. Tab. 206, from the 

 South Sea, may be noticed. 



Avicula BRUG., DESK AYES. Shell subequivalve or inequivalve, 

 often squamose externally. Hinge edentulous or with one or two 

 small teeth. Area oblique, submarginal, sometimes subindistinct 

 for the internal ligament. Internal surface of valves pearly. 

 Animal compressed, with mantle open, the margin incrassate, 

 cirriferous. Foot conical, vermiform, with byssus thick, the fila- 

 ments sometimes coalesced. 



Sub-genus : Avicula LAM. Shell oval, oblique, with ears large. 

 A cardinal tooth in both valves beneath the points. 



Sp. Avicula semisagitta LAM., Mytilus Hirundo L. in part, BLAINV. Malac. 

 PI. 63, fig. 8 ; Avic. Tarentina LAM., POLI Testae, utr. Sic. Tab. 32, figs. 

 17 21, &c. Fossil species also from the Muschel-kalk and other formations 

 are known. 



Meleagrina LAM. Shell suborbicular, with ears not produced and 

 hinge edentulous. 



Sp. Avicula margaritifera, Mytilus margaritiferus L., RUMPH. Amb. Rari- 

 tcilk. Tab. 47, figs, r, G; D'ARGENV. PI. 20, fig. A, BLAINV. Malac. PI. 



