328 ALFRED GIBBS BOURNE. 
“triple connections”’ and imagined that networks of capillaries 
existed in certain places, to which blood was brought by 
branches of both the dorsal and ventral vessels, and from 
which blood was carried away by branches of intestino-tegu- 
mentary vessels. I am now convinced (from a re-examination 
of my preparations of Megascolex ceruleus and a study of 
fresh preparations made for the purpose from another large 
Perichete) that this is not the case. I still believe it to be 
perfectly true that blood carried outwards from the dorsal and 
ventral vessels passes into intestino-tegumentary vessels, but in 
one place small capillaries from the dorsal vessel loop over into 
some branches of an intestino-tegumentary vessel, and in other 
places small capillaries from the ventral vessel loop over into 
other branches of the same vessel.! 
Intestinal Networks.—There is not quite so elaborate a 
system of blood-vessels in the walls of the alimentary canal as 
in Megascolex ceruleus, and there is not in a sense the 
same interest attaching to them as in that form, because their 
relations to the main trunks are muchsimpler. The intestinal 
networks are in the greater portion of the canal (from Seg- 
ment xiv backwards) directly connected with the dorsal vessel 
on the one hand and the ventral vessel on the other. There 
are no vessels having the relations of the intestino-tegumentary 
vessels of Megascolex ; there are, indeed, no vessels communi- 
cating at both extremities with capillary networks. 
In the anterior region, as far down as Segment x111, blood 
is carried to the canal wall by branches of the ventral vessel 
(ventro-intestinal vessels), and taken away by vessels which 
run into the anterior longitudinal vessels in the rest of the 
worm; there are similar afferent vessels, but the efferent 
vessels run into the dorsal vessel direct (dorso-intestinal 
vessels), The intestinal networks are best developed in the 
absorbent region. There the main vessels of the network run 
1 I have been unable to find any account in the literature at my command 
of the exact connections between the ultimate ramifications of the hepatic 
artery, the portal vein, and the hepatic vein, in the Vertebrate liver. It would 
be interesting to know if we have to do here with true “triple connections.” 
