VASCULAR SYSTEM OF PHERETIMA 389 
thirteenth segments there are ‘hearts’ in the ninth and 
seventh segments also to take blood into the ventral vessel. 
T also agree with Bourne (1) when he says, ‘ All the blood which 
enters the ventral vessel comes from the “hearts ’’, and that 
all the ventro-integumentary branches—those anterior to the 
‘hearts ’’, as well as those posterior to them-—-are efferent 
vessels. So far as the ventral vessel is concerned, they carry 
blood away from it.’ The ventral vessel, therefore, here as in 
TEx?-Fic. 11. 
B 
Semi-diagrammatic representation of ‘hearts’ in longitudinal 
sections, A is one of the ‘lateral’ hearts of the ninth segment 
with the valves in its lumen and a bulb-like dilatation at its 
ventral end before it joins the ventral vessel. d.v.=dorsal 
vessel ; ht.=heart; v.=valves ; si.v.=supra-intestinal vessel, 
the region of the body behind the thirteenth segment, is the 
distributing vessel and supplies blood through the ventro- 
tegumentaries to the body-wall, the integumentary nephridia 
as well as the spermathecae and seminal vesicles, the ovaries, 
and the oviducts. But it does not supply blood to the gut 
as it does in the hinder region ; there are no ventro-intestinals 
here, and the function of supplying blood to the gut here is 
taken over partly by the dorsal vessel which supplies blood to the 
gizzard in the eighth segment and the pharynx and oesophagus 
in front, and partly by the lateral oesophageals, These vessels 
Dd2 
