BRACHIOPOD A—'THOMSON. 
15 
throw out several branches on each side, and the middle pair in each valve bifurcate 
broadly near the anterior margin, the outer branches again branching repeatedly. 
Spicules occur in the sinuses and all the branches, as well as in the body wall, around 
the mouth, and in the arms. The latter are short, with relatively short cirri which 
contain slender, elongate, overlapping rod-like spicules. The body wall is stiffened 
with interlocking stellate spicules containing each only a few “ windows ” in the central 
part, and the surfaces of these spicules are finely spinose. Those of the ventral body wall 
are stouter than those of the dorsal. The body having been dried and the cirri curled 
in before examination of the spicules of the arms, the latter could not be satisfactorily 
exposed, but the absence of cirri socles and the presence of numerous branch-like main 
plates below was determined and agrees with the account given by Blochmann for the 
specimens from Schouten Island. Length, 33 mm., breadth 23 mm., thickness 19 mm. 
The specimen described above differs considerably both in size and beak 
characters from the type as figured by Davidson and by Blochmann. There are so 
many points of agreement, however, between it and the larger, more elongate, specimen 
described by Blochmann (1914) from Schouten Island, especially in the shape of the 
dorsal valve and the loop, and the spicules, that there can be little doubt that these 
are the same species. The more advanced beak characters of the present specimen, 
together with its larger size, may probably be correlated with its greater age. 
Mr. C. Hedley has kindly lent me for comparison a specimen from Cape Byron 
determined by him in 1908 as Liothyrina uva. This consists of a ventral valve 16-5 mm. 
in length, and agrees closely in shape and beak characters with the present specimen, 
and like it possess a fine radial striation. It is also doubtless to be referred to Lithy- 
rella fulva. 
Liothyrella ovata sp. nov. 
(Plate XVI, fig. 42; plate XVII, figs. 54, 55, 56; plate XVIII, fig. 63.) 
Habitat. —Station 10; off Shackleton Glacier (Davis Sea), 325 fathoms, 29th 
January, 1914. Sea-bottom, ooze ; temperature 1-65° C. A single shell. 
The shell is white in colour, ovate, with a blunt beak and a truncate front, the 
sides being rounded and passing gradually into the gently rounded front. The greatest 
width is very slightly in front of the middle. The hinge line is of moderate width and 
obtusely angled. Both valves are convex, the ventral more so than the latter. There 
is no marked sinus or fold on either valve, but a very faint indication of dorsal biplication. 
The lateral commissures are practically straight while the anterior commissure shows a 
very light ventral median depression corresponding to the median sinus of the dorsal 
biplication. The beak is short, sub-erect, without pronounced beak ridges, and is 
truncated by a fairly large epitkyrid foramen, which is marginate and possesses a small 
pedicle collar within. The surface ornament consists of numerous not very pronounced 
growth lines, crossed by a rather widely spaced faint radial striation. Dimensions—• 
Length 23 mm., breadth 19 mm., thickness 13 mm. 
