41 



LUCINID^. 



The mollusks composing this group exhibit shells which, 

 in form, texture, and ornament, strikingly remind us of 

 Venus and its tribe, whilst the animals seem more closely 

 connected with Kellia and its minute allies. The former 

 are equivalve, and usually more or less orbicular, their sur- 

 faces presenting all varieties of sculpture ; in some being 

 smooth, in others decussated or radiated by longitudinal 

 ribs, or sulcated by concentric furrows, or scored by wavy 

 markings disposed in elegant and regular patterns. The 

 muscular scars of their interiors present features of generic 

 importance, and the pallia! impression is always entire. 

 The animals have sessile siphons, unless the anal tube pre- 

 sented by certain Luchicc be regarded as a true siphon ; 

 more probably, however, it is only a great development of 

 the anal valve. They are sand or mud-inhabiting bivalves, 

 ranging through all depths of water, some of them being 

 littoral, others confined to the deepest explored abysses of 

 the ocean. The genus Corhis, of which we have no living 

 British examples, though during periods immeasurably dis- 

 tant its representatives inhabited our area, is a very beauti- 

 ful and conspicuous member of this tribe. 



The animals of several species of Lucina and that of 

 Corhis, have furnished the subject of some valuable ob- 

 servations communicated by the eminent French zoologist, 

 Valenciennes, to the Institute in 1845, and published in 



VOL. II. G 



