630 
right valve is slightly larger than the left. Length, 25 millimeters; height, 21 
millimeters. 
Locality: Shaly sandstone beds of the Loboo River, Batangas Province. 
Age: Upper Miocene. 
MACOMA Leach. 
Macoma rosariana sp. nov. PI. III, fig. 4. 
The cast of a very triangular form with a rapidly descending anterior margin, 
marked by a prominent sinus parallel to this edge. 
The figure does not at all bring out the sculpture, but there is enough on the 
cast to enable any one examining it to make out the rather prominent growth 
lines to be seen as small ridges from 2 to 3 millimeters apart. Length of shell, 
43 millimeters; height, 34 millimeters. 
This form is not greatly unlike WM. nasuta Carp. from the Upper San Pedro 
series (Pleistocene), Los Cerritos, California, 
It is quite difficult in these casts to distinguish between Tellina and Macoma. 
In this case, the writer has considered the more triangular and blunter shape 
and the rougher surface as indicating the latter rather than the former. 
Locality : Shaly sandstone beds of the Loboo River, Batangas Province. 
Age: Upper Miocene. 
ARCA Lain. 
Arca nodosa Mart. var. nov. batanensis. PI. II], fig. 6. 
Shell trapezoid, equivalve, with a wide amphiditic area, distant conspicuous 
beaks, and radial sculpture, a wide byssal gape, a long, straight, transversely 
dentate hinge line, with many similar teeth. (Zittel.) This shell, which is 
the commonest form in the Tertiary as well as the Recent deposits of these 
Islands, is quite similar to Martin’s 4. nodosa, however with the nodes not so 
prominent. It measures 20 millimeters in length, 11 millimeters in height, and 
the number of ribs is 22. The nodes are found only on the lateral ribs. 
Loeality: Shaly sandstone beds on Loboo River, Batangas Province. 
Age: Upper Miocene, 
The variety name of batanensis has been given because of the great 
abundance of this form in the beds above the Coal Measures on Batan 
Island, P. I. 
The writer has not as yet seen any living form which is quite like this. 
The living species are all much larger. The Arcidw are still the most 
abundant of our Philippine marine mollusca. 
LUCINA Brug. 
Lucina sp. indet. PI. III, fig. 8. 
A cast of a species, as yet undetermined, with very prominent beaks. A portion 
of the shell, still remaining, possesses a very fine seulpturing consisting of parallel 
growth lines. 
Locality: Shaly sandstone beds on Loboo River, Batangas Provinee, 
Age: Upper Miocene. 
SEMELE Schum. 
Semele (7?) dalli sp. nov. Pl. IV, fig. 5. 
This specimen is somewhat more triangular than the Semelid@ usually are, 
but its sculpturing and the possession of a shallow sinus parallel to the anterior 
margin make it resemble the form described by Dr. Dall in his “A Subtropical 
