110 PROVISIONAL AID TO THE STUDY OF TASMANIAN MOLLUSCA. 



(Ixxxii.) Family PETBicoLiDiE. 

 Genus Eupellaeia. (642-647.) 

 Shell elongated, moderately tumid, surface rugosely striated and 

 ribbed, distinctly gaping posteriorly ; hinge in the right 

 valve with two cardinal teeth, and a third very small, 

 but usually obsolete, anterior ; the middle one is 

 prominent, curved as in Petricola ; the posterior is 

 longitudinally lamellar, low and bifurcate ; in the left 

 valve are three distant and very unequal cardinal 

 teeth ; the middle one is similarly projecting as the 

 corresponding tooth in the other valve. Rup. lamelli- 

 fera, Conrad ; may be considered as a type of a group. 

 Dist. — Europe, Pacific, etc. 



(lxxxiii.) Family Cabdiidje. 

 G-enus Carditjm. (648-651.) 

 Shell ventricose, close or gaping posteriorly; umbones 

 prominent, sub-central ; radiately ribbed ; margins crenu- 

 lated ; pallial line more or less sinuated. Dist. — 

 World-wide; from sea shore to 140 fathoms. Gregarious 

 on sands and sandy mud. 



(lxxxiv.) Family CHAMiDiE- 

 Genus Chama. (652.) 

 Shell attached usually by the left umbo ; valve foliaceous, the 

 upper smallest ; hinge tooth of free valve thick, curved, 

 received between two teeth in the other ; adductor 

 impressions large, oblong, the anterior encroaching on 

 the hinge-tooth. Dist. — Tropical seas, especially 

 amongst coal reefs : fifty fathoms. West Indies, 

 Canaries, Mediterranean, India, China, Australasia. 



(lxxxv.) Family LuciNiDiE. 

 Shell orbicular, free, closed ; hinge-teeth 1 or 2 ; laterals 

 1 — 1; or obsolete; interior dull, obliquely furrowed ; 

 pallial line simple ; muscular impressions two, 

 elongated, rugose, ligament external or sub-internal. 



Genus Ltjctna. Brug. (653-655.) 

 Shell orbicular, white, sometimes divaricately striate ; umbones 

 depressed ; lunula distinct ; margins smooth or 

 minutely crenulated ; ligament oblique, semi-internal ; 

 hinge-teeth 2 — 2, latterals 1—1 and 2—2 or obsolete ; 

 muscular impressions rugose, anterior elongated 

 within the pallial line, posterior oblong ; nmbonal area 

 with an oblique furrow. Dist. — Universal. 



