IQI0.] J. STEPHENSON: On Bothrioneurum iris. 245 
itself. The paratrium, which is small, egg-shaped, without a cap 
of peritoneal cells, and possesses a hardly distinguishable lumen, 
arises from this portion of the tube a little beyond the end of the 
first part; its mouth is invaginated into the atrium. The last 
part of the tube, comprising only a short extent near the male 
aperture, is lined by a cubical or even slightly flattened epithelium 
(fig. 2). 
I am, however, doubtful if there is any such sharp division 
between the character of the cells of the first and second parts of 
the tube as is indicated above. In one of the series of sections, 
the cells of the first part of the tube, as well as the second, are 
mucous-looking cells, in appearance very similar to those of the 
clitellum in the same specimen ; and the cells of the second part 
of the tube are close-set like those of the first part, and not ragged 
in appearance. The differences may, therefore, be due to differ- 
ences in the functional activity of the cells. 
The ovaries’ are in the segment succeeding the testes. The 
female apertures have already been mentioned. The egg funnels, 
in the only specimen in which they were identified, are small, 
and the oviducts short and narrow. There are no spermathece. 
With regard to the other systems, the following remarks may 
be made. The alimentary canal shows very little differentiation 
from mouth to anus; in segment i what may be called the buccal 
cavity is lined by a flattish epithelium; this is succeeded by 
columnar cells in segment ii; in segments ii and iii the cells are 
higher than elsewhere, and this portion may be called the pharynx; 
a few muscular fibres radiate backwards in these segments, attach- 
ing the pharynx to the bodywall, and reaching the parietes in 
segments iii and iv. Masses of gland cells are present in connec- 
tion with the alimentary canal in segments iil, iv and v. Two of 
the most striking features in sections are the enormous parasitiza- 
tion of the anterior part of the alimentary canal by large sporozoa, 
and the great bulk of the chloragogen cells around the alimentary 
tube ; these latter begin in segment iv (cf. fig. 2). 
I have, in agreement with Beddard, failed to find any system 
of cutaneous capillaries. ‘The atria unite in the middle line under- 
neath the nerve cord, as described by that author ; the nerve cord 
is here very considerably flattened in a horizontal direction ; it 
contains, in the anterior part of the body, a tubular cavity 
(Neurochordrohrchen), which is double in the genital region, and 
may be so elsewhere (fig. 2). 
The original diagnosis of Bb. ivis, as given by Beddard, runs 
as follows :—Male pore single and median on xii. Clitellum wii, 
xiii. No integumental vascular system. No genital sete. Sper- 
matophores present to the number of one. 
It will be seen that the present specimens do not conform to 
this diagnosis, since (i) the male pore is not invariably on xii; (ii) 
nor is the clitellum invariably on xii—xii1; and (ii1)-the spermato- 
phores may be asmany asfive. Further differences are found in (iv) 
