136 ANATINIDA. 
outer laminze prolonged dorsally beyond the point of attachment. Foot 
more or less linguiform. Shell with the interior nacreous, more or less 
gaping at the extremities ; ligament external ; cartilage internal, placed 
in corresponding pits and furnished with a free ossicle. 
Genus, ANATINA—Lamark. 
Siphons covered with a rugose epidermis. Shell oblong, ventricose, 
very thin, often translucent, sub-equivalve ; umbones fissured, directed 
backwards ; hinge with a spoon-shaped cartilage process in each valve ; 
pallial sinus wide and shallow. 
A. tasmanica, Reeve, Conch. Ic, f. 20. Shell nearly equilateral, 
oblong, rather compressed, sub-hyaline, rather obsoletely granulated, 
sides rounded, but little gaping, posterior rather the narrower (Reeve.) 
Auckland. Collingwood. Australia and Tasmania. 
Genus, LYONSIA—Turton. 
Siphons short, separate at their extremities. Shell with the left 
valve slightly larger, thin; cartilaye plates oblique, covered by an 
oblong ossicle ; pallial sinus angular; interior sub-nacreous. 
L. vitrea, Hutton, C.A0.M., p. 61. Elongately oblong, very thin, 
slightly gaping and truncated behind; umbones sub-central, smooth, 
white, finely longitudinally striated ; pallial sinus extending to the centre 
of the shell, rounded. 
Eleight, “5); lengths *:7 5. 
Genus, THRACIA—Leach. 
Siphons divergent, separate nearly their entire length, their orifices 
fringed. Shell oblong, slightly compressed, attenuated and gaping 
posteriorly ; cartilage process thick, not prominent, with a cresentic 
ossicle ; pallial sinus shallow. 
T. nove zealandiz, Reeve, Conch. Lc., f 19. Shell somewhat 
triangularly ovate, rather solid, posteriorly rather broadly angled; left 
valve flat ; concentrically rudely plicately striated, especially towards the 
umbones ; umbones rather sharp, a little beaked, whitish, smooth 
(Reeve.) 
Possibly a variety of 7! australica. 
Genus, NEA*°RA---Gray. 
Siphons short, united, the orifices of both with a few long cirri, the 
anal with a membranous valve. Shell thin, transparent, generally pro- 
longed into a gaping beak behind; hinge with a small spoon-shaped 
process in each valve, and_a large lateral recurved tooth in the right 
valve, 
