38 AUSTRALASIAN ANTARCTIC EXPEDITION. 
SUBMARGARITA CREBRILIRULATA Smith. 
Valvatella crebrilirulata Smith, Nat. Antarct. Exped., i1., 1907, Moll., p. 11, pl. 11, fig. 9 
Id., Hedley, Brit. Antarct. Exped., i1., 1911, Moll., p. 4. 
Margarites crebrilirulata Smith, “ Terra Nova” Exped., Zool., i., 1915, p. 63. 
The spiral threads of this species vary considerably in their development ; they 
may be normal on the early whorls and gradually disappear on the last, or the upper 
surface may be lirate and the base smooth. A large example is 10mm. in height. 
From Commonwealth Bay : several dredged, January 20th, 1913, in 15-20 fathoms, 
on a floor of rock and brown alge; again numerous, September 3rd, 1912, in 25 
fathoms; nine, December 14th, 1913, in 45-50 fathoms ; and three from 55-60 fathoms. 
One specimen was taken in 3 fathoms in the Boat Harbour, Commonwealth Bay, by 
Dr. McLean, in 1913. 
SUBMARGARITA SMITHIANA sp. nov. 
(Plate V., fig. 58.) 
? Margarites sp. Smith, “ Terra Nova” Exped., ii., Moll., 1915, p. 63. 
Shell thin, turbinate, spire elevate, umbilicus narrow, deep, and spiral. Colour 
pale buff. Whorls about six, round and loosely coiled, parted by deep sutures. 
Sculpture: the surface is ornamented by raised spiral cords, which increase by inter- 
calation and consequently vary in size, space, and number as growth proceeds. They 
extend from the suture to the aperture, are often crowded and irregular; in one 
apparently adult individual they finally amount to about 30. But in a specimen of 
about five whorls there are only 15 cinguli, of which one on the shoulder, another at 
the periphery, and a third at the margin of the umbilicus are larger than the rest. A 
series of sharp elevated radial threads run obliquely backwards from the suture to the 
umbilicus; these are evenly arranged about their own breadth apart and are as 
prominent on the summit of the cinguli as in the hollows between them. Aperture 
subcircular, entire, lightly attached to the preceding whorl, outer lip simple, columellar 
margin a little expanded. Height, 11; maj. diam., 12; min. diam., 9mm. 
Six defective specimens were dredged, January 28th, 1914, in 240 fathoms, ooze, 
_ off the Shackleton Ice-shelf, in South Lat. 65° 20’ and East Long. 95° 27’. 
From his description S. smithiana appears to be identical with an unnamed species 
taken by the “ Terra Nova” Expedition, in 180-200 fathoms, in South Lat. 69° 43’ 
and East Long. 163° 24’. It is accordingly named as a tribute of respect to one who 
has done so much work on the Molluscan fauna of the Antarctic. 
