156 BULLETIN OF THE 
cell-rows. There certainly are no transverse cell walls and no very 
regular distribution of nuclei; and while they may be potentially equiv- 
alent to rows of cells, they certainly are not the same as the structures 
in the Trichotrachelide known as cell-rows. To use the expression, 
then, is to emphasize a morphological relationship which, if it exist, is 
much more distant than the use of this word would lead one to sup- 
pose. Bürger also described the regions of the intestine bounded suc- 
cessively by four, three, and two cells; but in spite of his strongly 
expressed doubts on the subject, he was led to regard the terminal 
orifice of the papilla as the anus, following the description of Verrill 
and Fewkes. It must have been poorly preserved material which gave 
the appearances shown in his Figures 25 and 29, for I am convinced 
that the supposed cuticular lining of the intestine does not exist. I have 
found nothing which supports his claim, set forth at length, that the 
intestinal lumen when apparently bounded by three cells is really 
formed at the expense of only one, and belongs to that cell alone. 
3. ANTERIOR CHAMBER. 
The anterior chamber is a prominent and characteristic feature of the 
anatomy of Nectonema. . Even in the living animal one can usually dis- 
tinguish its main features (Fig. 3) under a compressor. The semi- 
transparent area extends as far as the transverse partition which, at 
about 0.3 to 0.4 mm. from the apex of the head, cuts off this portion: 
from the general body cavity. In the living animal this partition is 
concave anteriorly, and apparently slightly thicker at the centre ; on 
sections it is seen to be covered on its anterior face by a thin peritoneal 
membrane, whose flattened nuclei (Plate VII. Fig. 95) may be easily 
discerned at intervals. I am not sure that this same peritoneal mem- 
brane lines the entire anterior chamber. It can easily be demonstrated 
over the lateral surfaces and around the osophageal cell, where similar 
nuclei may be demonstrated even under the dorsal commissure of the 
brain and farther forward. On the dorsal surface of the brain I have 
searched in vain for the nuclei or the membrane; yet it is equally im- 
possible to find where it stops, if it does not line the entire chamber. 
In alcoholic specimens much of the regular character of the partition 
is lost, and it is usually found to be more or less distorted, as the effect 
of the various processes through which the material has passed. The 
fibres of which it is composed run in all directions, chiefly radiating 
from the centre toward the body wall. They show frequent pale nuclei 
(Fig. 95). The partition is pierced by the oesophagus alone, and it 
