PAPHIIDA. 145 
C. radiata, Deshays, P.Z.S., 1854, ~. 348. Oblong, rounded in 
front and rather obliquely truncated behind, with fine concentric striz, 
which are slightly waved at the posterior end; teeth strong; bright 
salmon colour, paler towards the margin, and with fine waved interrupted 
radiating strize of darker. 
Height, °5; length, ‘9. 
Stewart Island. Philippines (Coll. Cuming). 
FAMILY—PAPHIID~. 
Animal as in Zé//inzde, siphons thick, diverging, separate from the 
base. Foot tongue like. Shell equivalve, closed, with a cartilage in an 
internal pit, and with a simple compressed primary tooth, and a rudi- 
mentary process in the place of the second tooth; pallial sinus small. 
Genus, MESODESMA—Deshayes. 
Oval or sub-trigonal, thick, compressed, closed ; ligament internal, 
in a deep central pit; a minute anterior hinge tooth and + lateral teeth 
in each valve ; muscular scars deep, pallial sinus small. 
M. novee-zealandie, Chemnitz ; Reeve, Conch. Ic., f. 21; P. 
rotssyana, Lesson, Voy. Coquille, Zool. \., p. 424, pl. 15, f. 43; MW. chem- 
nitzit, Deshayes; Quoy and Gaimard, Lc. i, p. 505, pl. 82, f. 9-11. 
Shell oblong-ovate, transverse, rather solid, nearly equilateral, sides 
rounded, anterior a little the shorter; whitish, irregularly striated, 
covered with a thin fulvous white shining horny epidermis (Reeve). 
Height, 1°5 ; length, 225. 
All over New Zealand, but more common in the North. Auckland 
Islands. 
The Natives call this shell “ kokota.” or “ pipi.” 
M. ovalis, Deshayes, P.Z.S., 1854, p. 336; Reeve, Conch. Ic., f. 7, 
Shell oblong oval, rather thin, compressed towards the margin, nearly 
equilateral, posterior side a little the narrower; shining white; rather 
obscurely striated ; partially covered with a blackish epidermis (Reeve). 
Probably the young of the last. 
M. ventricosa, Gray, Dief. N.Z, ii., p. 252; Voy. Erebus and 
Terror, Moll., pl. 3, f. 6. Ovate, wedge-shaped, truncated behind, thin. 
ventricose, opaque white, smooth, slightly concentrically striated ; 
covered with a thin nearly transparent horn-coloured epidermis ; edge 
thin ; lateral teeth short, smooth, compressed, close to the cartilage pit, 
the front one of the left valve the largest ; pallial sinus not quite reach- 
ing to the centre of the disc (Gray). 
North Shore. Cook Strait. (Dieffenbach). 
Differs from JZ. Za¢a in having the pallial sinus deeper, in being more 
inequilateral, and in having two obsolete keels radiating from the 
unibones to the margin down the anterior end of the valves, whereas in 
ata there is but a single obsolete angulation. It is very close to JZ. 
donacta, Lam., from Chili. 
