THE ANATOMY OF PHORONIS AUSTRALIS. 127 
inch from the end the body dilates rather suddenly to form 
the bulbous region (fig. 1, 0.), and then tapers off so as to 
terminate in a blunt rounded cone. At the tip is a fairly 
conspicuous pit, as in Sipunculus. Professor McIntosh (19) 
appears to regard this pit as being a special glandular organ, 
and figures sections at three different levels. I can find no 
special glandular cells, and from my fig. 35 it is seen to be 
merely a slight inpushing of the body wall, the pit being more 
or less completely filled by the cuticle. The stomach is here 
connected to the body wall by a ligament. 
The “oral” extremity carries the crown of tentacles, 
within which are placed the mouth, anus, and nephridiopores. 
The general surface of the body, when viewed with a lens, 
exhibits closely-set transverse wrinkles (fig. 3), which are pro- 
duced probably by the contraction of the longitudinal muscles, 
and have of course no segmental significance. Near the 
aboral extremity, in the region marked 0. in fig. 1, this 
transverse wrinkling is absent, but the longitudinal strie, 
which are faintly seen elsewhere, are here strongly marked 
(fig. 4). As will be seen later on, the muscular layers undergo 
a remarkable inversion in this region. 
In some parts of the body remains of the cuticle are seen, 
especially aborally. The crown of tentacles occupying the 
oral end of the body (figs. 1, 2) is supported by a ridge, the 
lophophore, which passes completely round one side of the 
animal, but on the opposite side turns inwards, before reaching 
the middle line. This enables us to distinguish the “oral ” 
from the “anal” side of the creature. On the anal side the 
crown of tentacles appears incomplete, or rather a little on 
each side of the middle line the lophophore curves inwards 
(fig. 6). In the space thus left three ridges are apparent. 
The middle, rather larger, encloses the rectum, and may be 
distinguished as the “rectal” ridge. Hach of the others is a 
nephridial ridge. These ridges are more prominent imme- 
diately between the tentacles, and are continued for some 
distance inwards, that is, towards the oral side (see fig. 7). 
At the terminations of these ridges are placed the anus and 
VOL, XXX, PART 2,—NEW SER. 1 
