268 
H. L. M. PIXIiLL. 
vessels, indicating the presence of a serum as well as 
corpuscles. 
Excretory System. — There are as usual a pair of excre- 
tory organs at the distal end ; they are small tubes bent once 
only on themselves, and each opens into the coelom on either 
side of a lateral mesentery by a small funnel. That into the 
posterior coelom has a process extending down the mesentery 
for a distance of about 160 ^ ; they are both closely applied 
to the transverse septum above. 
The tube, which is about 250 fx long, runs first outwards 
close to the mesentery, and then upwards embedded iu the 
basement tissue, forming a slight ridge visible on the outside ; 
it then turns inwards, running’ along the dorsal surface to 
open on one side and in front of the anus. 
The question as to how far the general peritoneum and the 
blood-corpuscles derived from it have retained their excretory 
fuuction is considered later. 
The Vasoperitoneal tissue (Glefassperitonealgewebe of 
Cori [3] or nutriment tissue of Ikeda [9], and constituting 
Kowalevsky’s corps adipeux) is developed on some of the 
capillaries on both sides of the digestive tube (Figs. 3, 4, vp. t.). 
It consists of the usual large flat cells with small nuclei 
at their outer ends. The contained yolk-spherules vary much 
in size and stain easily with eosin, Licht grun and other 
stains. Iron-li£ematoxylin can be washed out of them more 
easily than from the nuclei. 
Blood-corpuscles apparently in various stages of degenera- 
tion are also to be seen in the cell s (Fig. 16, d. b. c.j, and 
generally some fusiform corpuscles (/. c.). These are often 
especially numerous in the pre-ampulla where the vasoperi- 
toneal tissue is only present in small amount, and they have 
also been observed floating freely in the coclomic fluid, occa- 
sionally in the distal end i-iglic away from this tissue. Ikeda 
(9, p. 145) states that he has never found these corpuscles any- 
where iu Ph. ijimai, and thinks they are of no great physio- 
logical importance. I have sometimes found them in immense 
7iumbers, giving no sign of a nucleus, but generally showing 
