VASCULAR SYSTEM OF PHERETIMA Sila 
in the second segment. There are no ventro-intestinals in this 
region of the body. 
4. Lateral-oesophageal Vessels.—These are a pair 
of fairly large vessels in the first fourteen segments of the animal 
situated on the ventro-lateral aspect of the oesophagus. They 
are always found full of blood and can be easily seen. Behind 
the gizzard, i.e. in segments ten to thirteen, they are very 
intimately attached to the wall of the oesophagus and, as can 
be seen in sections, communicate with the oesophageal ring- 
vessels throughout these four segments by as many branches 
as the number of ring-vessels. In the region of the gizzard 
and in front, however, they are free from the wall of the gut, 
but receive a branch in each segment from the wall of the gut. 
The lateral oesophageals receive in each segment a pair of 
branches that bring back blood not only from the body-wall 
and septa of this region but also from the seminal vesicles and 
the spermathecae. They thus function here like the branches 
of the subneural and commissural vessels behind, which collect 
blood from the body-wall, the nephridia and other organs in 
coelom like the prostates. 
It only remains to be added that the lateral oesophageals are 
a continuation forward of the subneural vessel. In the four- 
teenth segment the subneural vessel forks into two, and each 
of the two branches loops round the nerve-cord and comes to 
lie dorsal to it and is continued forward along the ventro- 
lateral aspect of the oesophagus as the lateral-oesophageal 
vessels. 
(b) The ‘Hearts’ and the Anterior Loops. 
It will be seen from what we have described above that there 
is no direct communication between the dorsal and ventral 
vessels in the region of the body behind the thirteenth segment, 
but in the anterior thirteen segments the dorsal vessel com- 
municates directly with the ventral through the ‘ hearts’ in 
the seventh and ninth, and twelfth and thirteenth segments. 
It is only these four pairs of ‘ hearts’ that are connected with 
the ventral vessel ; but, besides these, there are other ‘ hearts ’ 
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