TUNICATA. 19 
This Leptoclinum is of a gleaming white colour, and is hard and brittle, and much 
more densely crowded with calcareous spicules than in the case of the preceding species. 
The spicules are especially abundant in the superficial layer of the test, making it white 
and opaque. In the deeper layer alongside the viscera of the ascidiozooids there is a 
certain amount of yellow pigment in the test. 
These are probably young colonies ; and although they do not seem to agree in 
character with any of the described Antarctic species of the genus, still the material 
does not seem sufficient for a satisfactory description of a new species. I therefore 
prefer merely to record that there is this second species of white Leptoclinum present 
in the neighbourhood of McMurdo Bay. 
POLYCLINID. 
AMAROUCIUM ANTARCTICUM. 
(Plate VI., figs. 8-13.) 
A single club-shaped colony (Plate VI, fig. 8) was obtained from “ Dredge off 
Coulman Island—13. i. 02—100 fathoms.” It measures 5 x 3 cm. in extreme breadth 
at the upper swollen part of the stalk, but the upper surface of the head, where the 
ascidiozooids are placed, measures 2 cm. in diameter. The figure is from a photograph 
representing the colony about one-fifth larger than the natural size. The shape is not 
unlike that of the European Amaroucium proliferum or A. argus. 
There is a little sand imbedded in the outer layers of the test (see figs. 9 and 10): 
not sufficient to give the surface a sandy appearance, as in the case of species of 
Psammaplidium, but just enough to make it gritty to the knife or needle. The large 
ascidiozooids are seen in situ in fig. 10, and fig. 11 shows one of them extricated from 
the tough test. 
There are many rows of stigmata (fig. 11), and their arrangement and character 
are seen from the enlarged fragment of the branchial sac (fig. 13). 
THALIACEA. 
SALPID A. 
There are two jars of Plankton, largely composed of Salpidz, in the collection, 
in addition to a number of tubes containing specimens of Salpa and Otkopleura that 
had been caught individually or picked out. Most of this Plankton material was 
obtained in far Southern, but not strictly Antarctic seas (such as 40° to 45° 8. Lat.), 
and it includes only well-known cosmopolitan forms. Still, as it is a part of the 
‘Discovery ’ Collection, these specimens and localities will be given with the rest in the 
following list. 
VOL. V. G 
