i88 7 .] 
The Norw. North-Atlantic Exped. 
9 
chambers through these fissures is indeed very doubtful; I have 
been unable to detect any indications of that. In one specimen, 
the extreme end of the rectum, with its anus, is a little projected 
by the contraction, and an excrementory plug of slimy sand occu- 
pies the anus. On removing this plug the folds of the inner wall 
of the rectum became visible (PL I fig. 4 c). 
On the inner wall of the gullet-tube there are an immense 
number of longitudinal folds, which are broken off by the contrao 
tions of the transversal muscles causing the folds to acquire the 
appearance of running transversally (Pl. I fig. 3 a). This relation chan- 
ges as soon as the oesophagus passes over into the intestine, as the 
longitudinal folds, here, appear much more prominently, although 
they, also, have, here, a bulging appearance, owing to the action of 
the transversal muscles (PL I fig. 3 b) ; but in the rectum they are 
still more distinct, and thicker, and extend in nearly straight lines 
down to the anus (PL I fig. 3 c), round which they collect (PL I 
fig. 3 d). There is no gullet-groove (siphonoglyphe). 
On making a transversal section of the outer wall of the gullet- 
tube and intestinal canal, fillet-formed protuberances of fibrillous con- 
nective-tissue are seen (PL I fig. 7e, ub), whose epithelial covering 
consists of long, narrow, cylinder cells with a very thin membrane, 
and an oblong nucleus with corpuscle surrounded by a transparent 
protoplasmic mass. The connective-tissue fillets are arranged in 
such manner, that a few of them are more prominent than others, 
and it appears as if they are broken off by the septa, as in the 
space formed between two septa the fillets reach far forward into 
the middle of the chamber, whilst they also diminish in breadth 
the closer they approach to the septa. The whole object appears, 
under the microscope, as if the gullet-tube and intestinal canal are 
surrounded by a collar of connective-tissue covered by cylinder 
cells furnished with ciliæ; but whether there is only one or se- 
veral ciliæ on each cell it has not been possible for me to ob- 
serve. 
These connective-tissue fillets may be regarded as, really, rudi- 
mentary septa, but there is this peculiarity about them, that they 
issue from the gullet-tube and intestinal canal, and not from the 
wall of the body; and that they increase in breadth the nearer 
they approach to the posterior part of the body of the animal, so 
that they become broadest round the rectum. Between the epithe- 
lium and the connective-tissue, there is an extremely fine membrane 
(Peritoneum?) to which cylinder cells are attached, and which covers 
