150 
. Ohs. A genus, containing but a small number of Species, in- 
stituted by Sowerby under the name we bave adopted. Lamarck 
appears not to liave been aware of tbe previous existence of tbis 
genus, wben be published it under tbe name of Crassina in bis 
Anim. sans Yertebr. He referred it to bis Nymphacees tellinaiTes; 
but we agree witli Sowerby, in tbe opinion, that its proper place is 
witb bis Gonques marine ; from all of wbicb it is distinguished by 
its cardinal teeth and interior impressions. 
Blainville in bis Manuel de Malacologie et de Concbyliologie 
places it as a division of bis genus Venus, under tbe following 
characters : 
Solides, epaisses, suborbiculaires, subequilaterales ; deux tr^s- 
grosses dents divergentes sur une valve, et deux tres-inegales sur 
Fautre ; les impression es musculaires reunies par une ligule sans 
sinuosite posterieure.’^ He informs us that Defrance has announced 
tbe existence of eighteen fossil species, and we described two in tbe 
Journ. Acad. Nat. Sci. 
Astarte castanea. — Specific character. Beaks nearly cen- 
tral ; epidermis chestnut-brown. 
Venus castanea, nobis. Jour. Acad. Nat. Sci., vol. ii. p. 273. 
Ohs. It is longer in proportion to its breadth than tbe danmoni- 
ensis of Montague, and is destitute of tbe fine and regular striae, 
witb wbicb tbe ohliquala is marked. PI. 1. 
Pandora. — Shell transversely oblong, inaequilateral, inequi- 
valve, unattached, regular, somewhat rostrated ; left valve flattened, 
witb from one to three teeth extended upon the inner surface of tbe 
shell, witb a fosset for tbe ligament ; binge margin inflected ', right 
valve convex, teeth one less than in tbe left valve, witb tbe corres- 
ponding fosset ', ligament internal, attached to an elongated fosset 
or cicatrice, which inclines towards tbe anterior margin ; muscular 
impressions two, distant, lateral. 
Animal very much compressed, elongated, in tbe form of a 
sheath, by tbe union of tbe edges of tbe mantle and its continua- 
tion witb the tubes, wbicb are united and very short ; foot small, 
thicker before, exserted by a large slit in tbe mantle ; branchiae 
pointed backwards and continued into tbe tube.^^ — (Blainville.) 
Ohs. Tbe binge teeth extend on tbe inner surface of tbe shell 
in some degree like those of Placuna, to which genus tbis seems 
to be allied, both by tbe position of tbe teeth and tbe perlaceous 
