74 LAMELLIBRANCHIATA. 



red, finely radiately ribbed, those on the hinder margin spinnlose. 

 Height, -75 ; length, '87. 



Cook Strait; Stewart's Island, 15 fathoms. 



FAMILY ISOCARDIIDJE. 



Cordate, swollen, umbones sub-spiral ; hinge with two cardinal and 

 two lateral teeth in each valve ; anterior lateral tooth rudimentary ; 

 pallial line simple. 



VENERICAKDIA. 



Equivalve, inequilateral, sub-orbicular, generally with radiating 

 ribs ; cardinal teeth oblique, directed to the same side. 

 Warm seas. 



81. V. australis, Quoy ; Gray, Dief. N.Z., il, p. 256. Sub- 

 orbicular, inequilateral, swollen, with about twenty-two nodulose 

 radiating ribs, the nodules on the hinder side sub-spinose ; lumile 

 cordate, umbones oblique, recurved ; margin plicated. Pale brownish 

 white ; interior white, more or less marked with rosy or purple. 

 Height, 1-5 ; length, 175. 



Common. Chatham Islands. Stewart's Island. 

 The young shell is slightly marked with reddish brown, and all the 

 ribs are sometimes sub-spinose. The Natives call this shell " purimu." 



82. V. Zealandica, Potiez and Midland, Gall, des Moll., 1838, 

 p. 1(56. Sub-oi'bicular, rather compressed, with about sixteen sub- 

 nodulose radiating ribs ; lunule lanceolate ; umbones rather oblique ; 

 margin plicated. Brown ; interior brownish white. Height, - 45 ; 

 length, '45. 



ORDER LTJCINACEA. 



Mantle lobes free below, united behind, without any siphonal 

 opening ; foot below, elongated and generally cylindrical. 



FAMILY Luc INID^; . 



Orbicular, free, closed ; hinge teeth one or two, laterals 1 or ob- 

 solete ; pallial line simple ; muscular impressions elongated rugose ; 

 interior dull, obliquely furrowed. 



LUCINA. 



White, umbones depressed, lunule distinct, ligament semi-internal, 

 anterior muscular impression elongated within the pallial line, posterior 

 oblong. 



Widely spread. 



83. L. divaricata, LamarJc, Anim. sans vert., vi., p. 226. Or- 

 bicular, sub-globose, with thin undulating bifarious strife, margin even, 

 no lateral teeth. Height, T12 ; length, T25. 



Common. Chatham Islands. India. Africa. North America. 



CRYPTODON. 



Inequilateral, sub-orbicular, thin, smooth ; at the posterior end a 

 depression from the umbones to the margin ; lunule large, sub-oval ; a 



