MARINE MOLLUSCA OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 343 
Chetopleura brucet, Iredale, sp. n. (Plate, figs. 24, 24a-d.) 
Shell of medium size, ovate, depressed, girdle fleshy, densely covered with hairs, the 
longer being very prominent on a bed of shorter ones, appearing to be grouped and 
longest near the sutures. Valves broad, with a well-marked keel, though not very high, 
the posterior valve having the mucro about the anterior third. 
Shell smooth, the lateral areas being indicated by a very faintly raised ridge. 
Down the median keel of the five centre valves is a row of pustules which do not 
reach to the mucro, and two parallel rows can be seen on either side, these rows show- 
ing on the anterior portion of the posterior valve; but on the first median valve this 
arrangement 1s not so apparent. 
Scattered radiating rows of similar pustules are seen on the anterior valve, where 
faint ridges are indicated ; similar sculpture is seen on the posterior part of the end 
valve. On the pleural areas of the median valves scattered pustules are also present, 
whilst the lateral areas have them also few and scattered. Otherwise the only feature 
is the concentric growth-ridges, which are well marked on each ridge, indicating regular 
growth in still water. 
The internal features are, as noted by Piuspry for C. peruviana, Lamk. (Man. 
Conch., xiv. p. 29, 1892), the anterior valve with 9, central valves 1, and posterior _ 
valve 9 slits. 
Hab.—Scotia Bay, South Orkneys. Station 325. One fine specimen only. 
Agrees closely with C. peruviana, Lamk., and seems to be the first record for the 
genus from east of South America. (T. IREDALE.) 
Lepidopleurus pagenstecheri, Pfeffer. 
Leptochiton pagenstecheri, Pfeffer, Jahrb. hamburg. wissenschaftlichen Anstalten, iii 
Jahrgang, p. 107, t. iii. fig. 3 (1886). 
Hab.—Scotia Bay, 9-10 fathoms. Station 325. 
THIELE considers this Chiton conspecific with ZL. kerguelensis, Haddon, from 
Kerguelen Island, but IREDALE does not accept this conclusion, though admitting the 
close alliance of the two species. 
Hemiarthrum setulosum, Carpenter. 
Hemiarthrum setulosum, Carpenter, MS., p. 13.—Dall, Bull. U.S. Nat. Mus. ii., (1876), p. 44. 
—Haddon, “ Challenger” Polyplacophora, p. 14, t. i. fig. 4; t. i, fig. 4a, 1.—Martens 
and Pfeffer, Jahrb. des hamburg. wissenschaftlichen Anstalten, iii. p. 108, t. ill. fig. 4 
(1886). 
Hab.—Station 325, Scotia Bay, 9-10 fathoms, on Fuci and other Alge. 
Very small and juvenile specimens, probably referable to the above. IREDALE also 
doubts the identity of the South Georgian Hemiarthrum with that described by Dat 
from Kerguelen Land, but more material is wanted for comparison. 
