18 
AUSTRALASIAN ANTARCTIC EXPEDITION. 
The anus is small, and the surrounding area is rather paler than the general tint 
of the skin. The nephridiopores are unrecognisable, being covered with mud. 
Internal anatomy (fig. 15).—There is only one pair of retractor muscles, which 
are attached near the nerve cord at about the middle of the body length, viz., 6 mm. 
behind the anus. 
The nephridia are pale pinkish-brown, small in size, only 2 mm. in length; the 
pores are situated just in front of the anus. 
The intestine presents 12-15 visible coils, circularly and tightly coiled in the 
anterior portion of the spiral, but posteriorly becoming irregularly arranged, so that i^ 
is difficult to count them accurately. 
The spindle muscle is very delicate, and I did not note any other attachments, 
except that the rectum is attached to the body wall by only a short membrane on 
either side. 
Locality .— 
Commonwealth Bay, Station 2, 318 fathoms. 
Distribution of the species. —Widespread in Northern and Arctic seas (Chamberlin). 
Remarks. —It agrees almost precisely with Selenka’s diagnosis of P. eremita Sars, 
with, however, the following exceptions :— 
(a) The skin is there said to be smooth for a few millimetres behind the 
introvert, but in this variety the papillae extend continuously over 
the surface. 
( b) Selenka found no spindle muscle, whereas in the variety it is present 
though very delicate and readily broken. 
(c) The papillae on the introvert are a little longer than on the body, 
whereas in the variety they are very distinctly shorter. 
(d) Further, Selenka’s figures of the papillae (pi. v, figs. 54, 55) from the 
hinder end of the body are much shorter than those in the variety, 
which resemble in their proportions those figured for P. semperi 
(fig. 57), where, however, they are longer than in the present 
worm. 
At first I suspected from the form of the papillae that I was dealing 
with P. charcoti Herubel, but the whole anatomy of the two differs. 
