UNRECORDED GENERA OF THE OLDER TERTIARY FAUNA. 189 
Genus Phragmorisma,* nov. 
Examples:—Thracia Watsoni, E. A. Smith, Challenger Lamell., 
p. 69, t. 6, figs. 5-55; Bass Strait in 38 to 40 fathoms. 
P. anatineformis, Tate; Eocene, Spring Creek near Geelong, 
and Table Cape, Tasmania. 
Shell externally like Thracia or Anatina. Internally with a 
large subumbonal plate in each valve. The plate is broad, con- 
cave on its superior face, pendent from the umbo and more or less 
parallel with the umbonal cavity, its anterior side is confluent 
with the test, but ventrally and posteriorly it is free. 
The shelly process in the umbonal cavity is peculiar in the 
family Anatinide, though a certain similitude is offered in Mya, 
but in that genus the plate is horizontal and not perpendicular ; 
Asthenotherus, Carpenter, is doubtlessly related, but of it the 
information accessible to me is not decisive enough to permit of a 
critical comparison. 
Thracia perscabrosa, mihi, does not belong here, and is I think, 
rightly located generically. 
PHRAGMORISMA ANATINAIFORMIS, spec. nov., Pl. xii., fig. I. 
Shell inequilateral, inequivalve, right valve compressedly con- 
vex, left valve flat ; rounded in front, perpendicularly truncated 
behind, a slight angulation defines the post-dorsal area ; the post- 
dorsal margin is straight, hardly sloping; the antero-dorsal margin 
is obliquely rounded; the ventral margin is straightish to about. 
the middle, whence it gradually rises to the front margin. The 
surface is plicately wrinkled concentrically (the wrinkles are 
distant, narrow and low, except in the umbonal region where they 
are subangular and crowded), granular-striated in the umbonal 
region and thence half-way to the front in the medial area, the 
rest of the surface densely granulated (the granulation larger on 
the post-dorsal area. Umbos small, acute, and turned backwards. 
Hinge-line of left valve projecting as a thin plate before and behind 
umbo, the posterior projection much wider and forming a lunule- 
* Phragmos, blocking-up, and ereisma, a support. 
