131 
Soc., S. Aust., 1887, p. 186, as a near alliance to that fossil- 
species. 
Lithodomus euneiformis, spec. nov. Pl. i., fig. 4. 
Shell cuneately-oblong, without any posterior angulation, 
widest near front, attenuating rapidly to the narrow truncated 
and thickened margin; anterior side very short, truncatedly- 
rounded ; ventral margin nearly straight, but slightly incurved 
about the byssal region and corresponding with an almost imper- 
ceptible depressed area, which descends with a backward inclina- 
tion from the umbo. Umbos large, tumid, involute, approximate, 
nearly terminal, but not protruding beyond the vertical plane of 
the anterior margin. 
Test, which is covered with a thick, brown, glossy epidermis, 
is marked with somewhat distant furrows, becoming on the pos- 
terior slope very prominent and subimbricate ; the surface is 
otherwise smooth and without sculpture. 
Dimensions.—Antero-posterior diameter, 17; umbro-ventral 
diameter, 8 ; sectional diameter through the umbos, 7. 
Habitat.—Occupying crypts in a friable consolidated shell- 
ooze in eight fathoms, two miles off Port Victoria, St. Vincent 
Gulf ; many examples (Dr. Verco). 
This is a very distinct species on account of its shape and 
absence of radial sculpture, unless it may prove to be Modiola 
pulex, Lamarck, of King George Sound ; the diagnosis of which 
is, however, so brief as not to be satisfactorily applicable to it. 
Myrina erenatulifera, spec. nov. Pl. i., figs. 11, lla. 
Test rather thick, moderately inflated, obliquely truncate-oval 
very inequilateral, equivalve ; covered with a thin, brown, glossy 
epidermis, which is raised into slender folds of growth. The 
umbones are prominent, inflated, approximate, incline-over 
towards the front, and are nearly terminal. The anterior outline 
is oblique, narrowly and regularly arcuate, interrupted only 
beneath the hinge-extremity by an inconspicuous byssal-sinus ; 
the posterior side is more arched and regularly rounded to the 
obliquely semicircular ventral margin; the dorsal outline is 
straight. The hinge-line is broad, transversely plicated at both 
ends, the plications being interrupted by a ligamental groove, 
which descends obliquely from the umbo ; there are about twenty 
plications on the anterior side, and about thirty posteriorly. 
The interior is bluish-brown, and glossy, with a paler or white 
clouding circumferentially. The edge of the valves is slightly 
thickened, particularly in the post-dorsal margin, which is fur- 
nished with from four to six tooth-like crenatures—the termina- 
tions of radial ridges. 
