GEPHYREA INERMIA-BENHAM. 
13 
point in all lies in front of the 50 per cent. mark. I used the same method 
in dealing with the specimens from Commonwealth Bay, and find that the 
ventral retractors in the three individuals measured lie at or behind this 
halfway mark. It would, of course, be necessary to make measurements of 
a greater number of specimens in order to make sure that this difference is a 
real one before one can make use of it as a specific or varietal character. 
It appears that in all these southern varieties the dorsals arise in the 
anterior third, and the ventral retractors approximately in the middle third 
of the body length. But the mode of statement followed by Michaelsen 
and by Fischer in reference to these points makes it difficult to tabulate their 
exact position. 
It seems, at any rate, impossible to use these positions for specific 
or varietal purposes, and we are driven back to the skin, its naked eye 
appearance and its microscopic structure. 
Using this criterion the present specimens agree with P. margaritaceum, 
var. capsiforme. 
In general appearance to the naked eye, P. socium seems to agree 
with this, for Lanchester states that in it the skin is “ smooth, thin, semi¬ 
transparent, with minute papillae, barely visible under a hand lens”; and 
P. georgianmn also has a smooth, shining, silvery skin, sufficiently translucent 
for the internal organs to be seen dimly through it, as is the case with the 
smallest of my specimens. But the other two species from South Georgia 
have dark coloured and opaque body walls. 
In regard to the form and proportions of the skin papillae there seem 
to me considerable differences, for whereas in Michaelsen’s species and in 
P. socium the papulae are pear-shaped, constricted at the base, and have a 
breadth much less than the height, namely, from One-fourth to one-half, 
in the Commonwealth Bay forms they are low, rounded, only slightly 
prominent, with a width greater than, or at least only equal to, the height. 
For this reason, therefore, I have been unable to accept Theel’s opinion 
that all of them are to be included in the northern species. 
Phascolosoma mawsoni, sp. nor. 
(Plate 11, figs. 3-11.) 
More than fifty small Phascolosomids present characters which appear to warrant 
the formation of a new species. . It is true that the recent literature at my disposal is 
