988 PELECYPODA. [Eulamellibmnchia. 



dorsal margin very long, convex, descending ; basal margin broadly 

 rounded. Lunule, not distinctly denned, not, or only very lightly, 

 margined. Escutcheon wanting. Sculpture consisting of low broadly 

 rounded radiate ribs, obsolete on the posterior dorsal end, crossed by 

 distant fine concentric ridges, which are higher on the anterior end. 

 Colour reddish-brown, paler behind, or chocolate-brown. Interior 

 generally bluish-white, with dark purple at the posterior end, some- 

 times quite white, porcellanous. Margins crenulated, coarsely on 

 the posterior ventral part, much finer anteriorly. Hinge moderately 

 strong, arcuate ; right valve with 3 cardinals, the anterior small, 

 vertical ; the second a little oblique, strong, triangular, grooved ; 

 the posterior tooth long, horizontal, strong, and grooved ; left valve 

 with 3 cardinals, the anterior vertical, strong, triangular, and faintly 

 grooved ; the second very oblique, stout, and deeply grooved ; the 

 posterior cardinal a long and sharp thin lamella, parallel to the dorsal 

 margin. Ligament very strong, deep-set, but prominently raised on 

 the outside, with a strong internal resilium. Adductor-scars subequal, 

 pyriform, the posterior slightly larger, not very much impressed. 

 Pallial line distinct, distant from the margin, the pallia! sinus short, 

 broad, trigonal, free. 



Length, 56 mm. ; height, 49 mm. (figure in " Erebus and Terror ") 

 Length, 47mm.; height, 40mm.; diameter, 29mm. (usual size)- 

 Length, 65 mm. ; height, 50 mm. ; diameter, 36 mm. (specimen from 

 the Auckland Islands). 



Type in the British Museum. 



Hob. Common throughout New Zealand. Chatham and Auck- 

 land Islands. Kermadec Islands (Captain Bollons). Also Kerguelen 

 Island. 



Remarks Specimens from brackish water are generally very 

 small and much corroded. At the Auckland Islands the species at- 

 tains a very large size, the shells are very heavy, the colour uniformly 

 chocolate-colour, the interior white without purple markings, and the 

 lunule is mostly quite inconspicuous. They may be considered a 

 distinct variety. 



Maori. Huai or pipi (teste Hutton and Captain Bollons). 



Fossil in the Miocene and Pliocene. 







Sect. 2. LIROPHORA, Conrad, 1863. 



Lirophoru, Conrad, Proc. Acad. Sci. Philad. for 1862 (1863), 575, 586. Type : 

 Venus athlcta, Conrad ; a Recent species is V. paphia, L. Clausina, 

 Romer, 1857 ; not of Brown, 1827. Anaitis (paphia), Fischer, 1887 : 

 not of Tryon, 1884. Anaitis (part), Romer, 1857 ; not of Duponchel, 

 1829. 



Sculpture of broad concentric waves, attenuated and often con- 

 spicuously lamellose distally ; radially striate ; ligament not covered 



