TUNICATA OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 307 
the characteristic smooth test and translucent grey tint, and they also agree closely 
in internal details with the Challenger specimens from shallow water off the Falkland 
Islands. 
MrcuaELsen has suggested that this species and Paramolgula gigantea (Cunningham) 
are the same. No doubt they are related forms; both belong to the restricted genus 
Paramolguia, having only broad, ribbon-like longitudinal bars but no true folds in the 
branchial sac (a fact I overlooked in drawing up my “ Revised Classification of the 
Tunicata” in 1891, as MicuarLsEn has pointed out), but I do not consider them as 
identical. In addition to differences in the external appearance—the shape and the 
condition of the test—the branchial sacs are not alike in detail, and the dorsal tubercles 
differ widely. I give here a figure of the dorsal tubercle (Plate, fig. 9) of P. gregaria 
from the Scotia collection for comparison with that of P. gigantea figured in the 
Challenger Report. 
Lesson figures his species with five lobes round each aperture, but that is no doubt 
an error. The branchial aperture has six and the atrial four lobes. 
Paramolgula horrida (Herdman) (?). (Plate, figs. 10 and 11.) 
Locahty.—Station 118, on hulks, Stanley Harbour, Falkland Islands. 
I have very little doubt that this single large specimen (measuring 7°5 cm. in length 
and 5°5 cm. in breadth) belongs to the same species as the specimen from “off the 
Falkland Islands, 5-12 fathoms,” which I described in the Challenger Report as Molgula 
horrida. They both fall within the more modern genus Paramolgula, separated off 
from Molgula by Traustept because of the absence of true folds in the branchial sac. 
As the Challenger description was drawn from a single specimen, and as this Scotia 
Specimen differs a little in detail, it may be well, in the interests of a fuller knowledge 
of the species, to add a few of the characteristics of the individual before me. 
The shape is irregularly ovate, and flattened, and the colour is a very dark 
brown. The other external characters can be seen from the figure (Plate, fig. 10). 
The Test is leathery and rough on the surface. It is thin but tough, and dark 
but smooth and glistening on the inner surface. The Mantle is dark brown and 
opaque. It is thick, but soft and not muscular, or at least the muscles do not form 
obvious bands. 
The Branchial Sac has on each side seven wide longitudinal vessels which look like 
narrow folds. Between the distant wider transverse vessels, narrower intermediate ones 
branch in all directions in a dendritic manner, so as to form rounded and oval and 
variously shaped meshes in which the stigmata lie. The stigmata are also rather 
irregular in arrangement, being in some parts in spirals and in other places side by side 
in rows (see fig. 11). 
The Tentacles are of different sizes, there being eight larger much branched, with 
some smaller ones between. 
