336 ALFRED GIBBS BOURNE. 
Latero-longitudinal and Subneural System.—Hav- 
ing already spoken of the main vessels of this system, and 
made various references to their branches and detailed the 
distribution of the ventro-tegumentary vessels, which run for 
the most part strictly parallel to the branches of this system, 
it is not necessary to do more than refer the reader to fig. 27, 
where this system is shown throughout in blue. 
CouRSE OF THE BLoop. 
I have found it convenient to refer to the course taken by 
the blood in describing the anatomy of the vascular system, 
and I have, in writing of Megascolex ceruleus, dealt at 
length with certain general problems relating to the blood-flow 
in earthworms (see also below, p. 42), so that I need only sum- 
marise here the chief facts with regard to Moniligaster 
grandis. 
The blood flows forwards in the dorsal vessel, and while a 
little passes on in the anterior portion of the dorsal vessel, 
most of it is forced down into the ventral vessel by means of 
the hearts (chiefly the three anterior pairs) and is distributed 
by the ventro-tegumentary vessels on the one hand, to peri- 
pheral capillaries, and by the ventro-intestinal vessels on the 
other hand, to the intestinal capillaries. 
The peripheral capillaries in the region of the body behind 
the hearts are also supplied, to an extent which probably varies 
from time to time and is, I expect, never very great, from the 
dorsal vessel by means of the dorso-tegumentary vessels. 
The blood sent to peripheral capillaries is returned by the 
latero-longitudinal and subneural system to the most posterior 
pair of hearts, and the blood sent to the intestinal walls is 
returned by the dorso-intestinal vessels to the dorsal vessel. 
for Lumbricus. Upon my premises I do not think that the logical out- 
come of Benham’s view is tenable. 
But, apart from all this, 1 have investigated the arrangement of valves 
connected with these vessels in Lumbricus, and 1 think that it resembles 
that which obtains in Moniligaster. 
