69 
the foremost part of the upper side. Front margin abruptly des- 
cending, but little convex, strongly bent into the almost straight 
under side, hind margin produced-rounded, upper margin long, a 
little curved. Sculpture: 14 strong radiating costae, strongest in 
the left valve, of which 9 directed to the posterior margin some- 
what flexed upwards with their ends, elevated, rather compressed 
(most so the uppermost ones), and 5 lower costae in the median 
part; front half of the shell without radiating sculpture; besides ir- 
regular concentric lines, in the posterior and upper parts raised as 
lamellae Crossing the costae and lending them a subsquamose ap- 
pearance. Colour white, dorsally brownish. Interior white, brownish 
behind and above; mantie line with a very small sinus below the 
posterior adduclor. Anterior adductor scar small, ovate, not dis- 
tinctly separated above from the retractor scar, posterior one 
broader, rounded ovate. Hinge-plate narrow. Hinge: left valve with 
a single median Cardinal; shell margin depressed on both sides of 
it; right valve with 2 prominent stout teeth embracing the left one, 
and fitting into the sockets of the left valve margin; no cardinals 
in either valve. Ligament external, long, thin, with a strong resi- 
lium. Dimensions: L. 4, h. 2.6, crass. 2.2 mm. — Locality: Auck- 
land Island: 41 (Masked Island), 1 empty, somewhat injured shell. 
Externally this species is strikingly similar to a Cardita caly- 
ciilata; but the hinge shows quite different characters and proves 
that it is referable to the genus Kidderia. It is similar to K. bi- 
color in the teeth and the shape of ligament and protoconch; only 
a slight difference is present between their left valves which is, 
however, easily explainable in the obliteration of the foremost tooth 
(4a) of the new species; even in K. bicolor it is not constant. A 
further difference is that in K. bicolor the retractor muscle scars 
are well separated from the adductorial ones. Also in K. bicolor 
a tendency to forming a small sinus of the mantie line is observ- 
able. The participating of the shell margin in forming the left 
Cardinal sockets is no doubt a secondary apparition. 
Neogaimardia vostellata (Tate). 
(PI. II, fig. 57; text-figs. 17—19.) 
Mr. Medley, who has kindly verified the identificaton of spec- 
imens sent, communicated me the following references concern- 
