162 ARCIDA. 
panded, then truncated, concentrically rudely plicately striated ; black 
(Reeve, species 122.) 
Length, 3°3; Height, 1°6 inch (from Reeve’s figure.) 
Shell thin, much compressed, of a yellowish-olive green, not rayed, 
nearly smooth, with a few distant obscure, short, divergent corrugations 
on the broad umbonal slope; hinder dorsal edge somewhat curved and 
elevated ; ventral margin scarcely retuse ; beaks not prominent ; nacre 
dirty white ; cardinal teeth laminar (Reeve’s species 386.) 
Length, 2°15; height, 1-2 inch (from Reeve’s figure.) 
River Clutha. (F. W. H.) Auckland. (Dr. Sinclair.) 
Both these shells can hardly belong to the same species, but I am 
not able to refer to the original description. What I take to be U. 
Jutulentus, is distinguished by its tolerably uniform longitudinal grooy- 
ing, and somewhat resembles Reeve’s figure, No. 122. I cannot say 
which of Reeve’s references is correct. 
Sub-Order—A reacea. 
Mantle edges free all round ; foot large; hinge teeth many, sym- 
metrical. 
FAMILY—ARCID. 
Animal oblong. Mantle freely open, simple or fringed. Mouth 
surrounded by labia formed out of the extremities of the branchiv ; no 
true palps. Foot oblong, bent, grooved throughout its length -so as to 
form a disc with plain or slightly crimped margins. Shell not pearly 
within, closed, or gaping inferiorly. Hinge of numerous teeth disposed 
in a straight or curved line ; equivalve. 
Sub-Family—A reine. 
Gills sub-pinnate, separate from each other behind ; a byssal groove 
at the base of the foot. Shell with the hinge margin straight ;_ cartilage 
in small marginal pits. 
Genus, BARBATIA—Gray. 
Oblong or sub-quadrangular, covered with a rough but perishable 
epidermis ; hinge of numerous teeth, of which the central ones are 
the smallest; the lateral ones increasing in size and getting more 
oblique. 
B. decussata, Sow, P.Z.S., 1833, A. 18; Reeve, Conch. Ic., f. 81. 
Oval-elongate, margin sinuated, smooth or sometimes crenulated in the 
young, covered with a brown hairy epidermis ; surface with fine radia- 
ting ribs, decussated by longitudinal striz ; brown or yellowish ; interior 
white, varied with brownish purple. 
Pleight. 1-255 senstiy2.6. 
Auckland to Stewart Island. Australia. Pacific Ocean. 
B. pusilla, Sowerby, Proc. Zool. Soc., 1833, p. 18; (2 A. donacifor- 
mis, Reeve, Conch. Lc, f. 104.) Ovato sub-rhomboidal, white, concen- 
