444, E. A. ANDREWS. 
into the cavity of the penultimate region 8. Owing to the 
absence of the digestive tract, the appearance of the tip of the 
process is quite peculiar in section, and this backward exten- 
sion of the penultimate body-cavity space makes it the actual 
termination of all the sections. Thus the last appearance of 
the body cavity is as two small pits in the body-wall, on either 
side of a ridge that passes along where the nerve-cord is about 
to emerge from the ventral body-wall; these are ventral and 
belong to the region 8. Dorsally, the terminal region 9 ends 
bluntly, with no trace of any anal invagination or indications 
of a digestive tract. 
In other words, the septum between 8 and 9 sends back a 
nearly horizontal arch over the nerve-cord, and then cuts off a 
small ventral coelomic space that ends at the extreme tip of 
the process as a pair of pits, one right and one left of a slight 
median ridge. 
Where this peculiar left process joins the main trunk of the 
animal we find all its longitudinal organs continuous with 
those of the trunk; the nerve-cord joins the main nerve-cord, 
the ventral blood-vessel the main sub-intestinal vessel, and 
the longitudinal and circular muscles are directly continuous 
with those of the main trunks. 
The digestive tract of the trunk is in no way affected by the 
presence of the lateral process. 
As might be anticipated from the external views (figs. 7 
and 8) the arrangement of the septa in this region of union is 
by no means simple nor readily made clear. As will be seen 
in the horizontal section (fig. 10), the septa here are much 
enlarged and distorted, so that they lie beyond the planes of 
demarcation between external rings. 
With some considerable success we may attempt to trace a 
septum for each external groove, but errors easily creep in. 
In the lateral process itself the septa are but elongated 
and forced inwards towards the trunk, so that from 3—2 and 
2—1 we pass to the much distorted septum 1—95 that reaches 
in almost to the digestive tract of the trunk. Each body- 
cavity has its appropriate nephridia. 
