MOLLUSCA.- HBDLEY. 
31 
Ptychocardia rudis sp. nov. 
(Plate III., figs. 35, 36, 37.) 
Shell rhombo-cordate, much inflated, thin, radially bicarinate, dorsal margin short, 
posterior truncate, ventral bisinuate, anterior projecting but with a median insinuation. 
Colour bufi. Umbo prominent, incurved, polished. Lunule large, prominent, radially 
striated, limited by a wide and shallow furrow. Sculpture, the larger carina is median, 
projecting more than its posterior fellow, the whole valve overrun by sharp elevated 
threads separated by rather more than their interstices. Increasing by intercalation 
the threads amount at the margin to about 66. The interior is almost nacreous, ribbed 
by the impression of the external sculpture. Muscle scars invisible. Hinge with two 
small divergent cardinals in each valve. Height, 8 ; length, 6 ; breadth of conjoined 
valves,. 6'5mm. 
This species is a little shorter and more strongly featured than P. vanhoffeni, the 
median keel projects further and the radial threads are sharper and closer. 
Ten specimens dredged, December 28th, 1913, in 288 fathoms, ooze, off the Mertz 
Glacier, Adelie Land, in South Lat, 66° 52' and East Long. 145° 30'. 
PSEUDOKELLYA STILLWELLI Sp . 710 V . 
(Plate III., figs. 38, 39.) 
Shell small and frail, cordate-orbicular. Colour shading from pearl grey on the 
umbones to buff at the margins. The entire valve is sculptured by very close and very 
small radiating threads which increase in size as growth proceeds ; at irregular intervals 
these are crossed by widely-spaced concentric growth lines. Ventral margin finely 
crenulated by the radial sculpture. The hinge has in the right valve one cardinal and 
one lateral and in the left two small cardinals and one lateral tooth. Height, 5*5 ; 
length, 5*5mm. 
This is named in honour of Mr. F. L. Stillwell, a geologist of the Main Base party. 
Judging from illustrations it is near to P. cordiformis Smith, but is narrower, more 
symmetrical, and with finer sculpture. It is evidently a smoother shell than P. gradata 
Thiele. 
One valve and some fragments, December 28th, 1913, from 288 fathoms, ooze, 
off the Mertz Glacier, Adelie Land, in South Lat. 66° 55' and East Long. 145° 21'. 
Another valve and fragments, January 27th, 1914, from 120 fathoms, hard ground, in 
the Davis Sea, in South Lat. 66° 8' and East Long. 94° 17'. 
Kellia nimrodiana Hedley. 
Kellia nimrodiana Hedley, Brit. Antarct. Exped., ii., 1911, p. 4, pi. 1., figs. 1-4. 
From Commonwealth Bay : two, September 4th, 1912, from 25 fathoms, and one, 
December 21st, 1913, from 55 to 60 fathoms. 
