20 AUSTRALASIAN ANTARCTIC EXPEDITION. 
PHILIPPIELLA BAGEI sp. nov. 
(Plate L, figs. 5, 6, 7.) 
In Antarctic waters is developed Philippiella,* a genus the simplicity of whose 
features suggests that it may be either a primitive or a retrograde member of the sub- 
family Philobryine. Here I would include P. ungulata Pfeffer, P. quadrata Pfefter, 
P. limoides Smith, P. levis Thiele, P. tumida Thiele, P. bagei Hedley, and P. orbiculata 
Hedley. But I would now exclude P. crenatulifera Tate, and P. rubra Hedley, which, 
under a misapprehension of the original diagnosis, I formerly included (Proc. Linn. 
Soc. N.S.W., 1904, p. 208) here. For these I now propose a genus Notomytilus, type 
Philippiella rubra Hedley. The Philippiella proper are characterised by large size, 
profuse epidermis, smooth surface, thin shell, and weak, undeveloped, toothless hinge. 
The edentulous hinge is exactly correlated with a far southern habitat. 
The ligament is elongate and horizontal, that is, it runs along the dorsal margin 
instead of descending obliquely across the hinge-plate as in Hochstetteria. There are 
neither anterior nor posterior crenulated areas nor dysodont teeth as in Philobrya and 
Hochstetteria. The anterior dorsal margin of both valves in Philippiella project and 
interlock, thus acting as cardinal teeth. The anterior end of the valve is less abbreviated 
than in related genera. Apart from size and the prodissoconch shield, there is a striking 
resemblance between Philippiella and Meleagrina. Cardinal features, so useful for 
the discrimination of Philobrya, are here wanting, so that contour is left as the chief 
guide in distinction of species. 
The valve of P. bagei is ovate acuminate, with the anterior side considerably 
developed. The margin of the right is sometimes bent in, while the left over-reaches 
it. Prodissoconch small, flat, semi-lunate. Surface of adult smooth, on which fine 
concentric and radial threads form microscopic reticulations. Byssus, a bunch of 
numerous strings leading through a narrow chink high on the anterior side. Epidermis 
long dense imbricating leaves like that of the pearl-mussels, projecting far past the seat 
of the valve. Each leaf has a mid-rib, and this alone continues on the upper part of the 
valve. Inner ventral margin smooth. This species is like, but larger than, P. limoides 
in which the anterior and dorsal sides meet at a more acute angle, the me 1s Heeper 
and the crenulations on the inner ventral margin strong. Height, 13-5; length, 12; 
depth of conjoined valve, 7mm. ; aan” 
This shell is named in honour of Captain R. Bage, of the main base party, who 
subsequently was killed in action at the Dardanelles at the early age of 27. He was 
leader of the southern sledge party, and was one of those who volunteered to endure 
a second Antarctic winter for the sake of his lost leader. 
A couple of dozen were taken alive attached to weed and shell in 3 and 25 fathoms ; 
one, December 14th, 1913, in 45-50 fathoms ; and, again, one in 55-60 fathoms December 
21st, 1913, all in Commonwealth Bay. : 
* Pfeffer.—Jahrb. Hamb. Wiss. Anst., iii, 1887, p. 119. 
