140 MACTRIDA, 
shorter, attenuated; nght valve with two lateral teeth on each side; 
left valve with the anterior hinge tooth bifid, and the anterior lateral 
deeply notched ; cartilage pit broad and flat ; pallial sinus reaching to 
the centre of the shell; white, with brown spots and dashes ; covered 
with a thin brown epidermis. 
Height, 2°5 ; length, 4. 
Stewart Island, 25 fathoms. North Island. 
Genus, ZENATIA—Gray. 
Equivalve, inequilateral, oblong, umbo anterior, sub-marginal, gaping 
at both extremities, covered by a thick and _ projecting epidermis ; 
cartilage plate prominent, cardinal teeth distinct, no lateral teeth ; pallial 
sinus deep, horizontal ; hinge posterior. 
Z. acinaces, Quoy and Gaimard, l.c., p. i1., p. 545, pl. 83, f- 5-6; 
Reeve, Conch. Ic. (Lutraria), f. 14; Chenu, f. 248; Z. cumingtana, Deshayes, 
P.Z.S. 1844; Reeve, Conch. Ic. f. 13.-. Shell thin, compressed, oval 
oblong, arcuate, greyish-yellow, interior emerald green, behind finely 
striated, outside greyish-yellow, the umbo almost white ; interior white, 
pearly and iridescent, yellowish towards the umbo (Q. & G.) 
Length, 1 inch 10 lines ; height, 9 lines; thickness, 4 lines. 
Auckland to Dunedin. Australia. 
The figures of Reeve, No. 14, and of Chenu, are very bad. 
Z. deshayesii, Reeve, Conch Lc. (Lutraria) f. 1; Z. solenoides, 
Desh. P.Z.S., 1854; nec Lamark. Shell elongately oblong, thinnish, 
rather narrow, concentrically densely striated, striae somewhat wrinkle- 
like ; sides equally rounded, the anterior very long, much gaping. Rust- 
flesh tinged, covered with a greenish olive epidermis (Reeve.) 
No doubt the same as the last. 
Genus, VANGANELLA—Gray. 
Transversely oblong, thin, compressed, covered with a smooth 
epidermis, sub-equilateral, rounded in front, attenuated and sub-angular 
behind, with two divergent ribs in the interior; cardinal teeth of the 
left valve near together, those of the right valve separated ; lateral teeth 
small, thin ; ligament sub-external, marginal, cartilage-plate, elongated, 
not very deep. 
New Zealand only. 
V.taylorii, Gray; Ann. Nat. Hist., 1853, x1., p. 476; Voy. 
Erebus and Terror, pl. 2, f. 5; Chenu, f. 249; Adams Gen. of Moll, pl. 
102, f. 2; Lutraria lanceolata, Reeve, Conch, Ic., f.17. Shell rather 
compressed, white, smooth, covered with a pale: brownish-white polish ; 
periostraca darker coloured on the upper part of the front edge; the 
upper hinder slope irregularly wrinkled with periostraca (Gray). 
Cook Strait to Dunedin. 
Genus, RAETA—Gray. 
Shell cordiform, ventricose, thin ; sub-angular and slightly gaping 
