161 
vessel (figs. 25, 56). This is usually first distinguish- 
able posteriorly about the middle region of the stomach, 
and becomes more clearly differentiated as it proceeds 
forwards. Each receives blood from the dorsal and sub- 
intestinal vessels through the gastric plexus, and opens 
into the auricle, which is a thin walled expansion, 
probably of the gastric vessel. 
After giving off the lateral csophageal vessel, the 
auricle opens into the ventricle, the walls of which are 
muscular, and drive the blood into the ventral vessel. 
The lateral cesophageal vessel on each side gives off a 
branch to the esophageal pouch, and then runs forward, 
supplying the lateral walls of the esophagus, and breaks 
-up into capillaries between the first and _ second 
diaphragms. 
On each side of the nerve cord there is a small vessel 
which accompanies the cord along the whole length of the 
body. These neural vessels arise in front in the triangular 
area between the cesophageal connectives by union of 
capillaries from that region. Branches of the ventral 
vessel enter into connection with them in the five segments 
(second to sixth inclusive). 
The vessels of the body wall are well developed 
(figs. 24, 36). There are on each side two longitudinal 
vessels distinguishable from the other vessels of the body 
(1) the nephridial 
longitudinal vessel which runs on the inner face of the 
wall by their somewhat greater size 
body wall just ventral to the level of the nephridiopores, 
and (2) the more obvious and more important dorsal longi- 
tudinal vessel which runs parallel to but above the former, 
being slightly dorsal to the level of the notopodial setal 
sacs. The former (the nephridial longitudinal vessel) is 
only well marked in and for a short distance anterior and 
posterior to the nephridial region. The dorsal longitu- 
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