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W. A. HASWELL. 
is condensed to form definite somatic and splanchnic layers, 
the former closely applied to the muscular layer of the body- 
wall, the latter giving rise to an investment for the ovary in 
addition to the usual layer investing the narrowed intestine, 
here sunk in the dorsal body-wall. 
Further forwards (fig. 9) a pair of vertical longitudinal 
septa are formed very much as in the male, the median 
chamber enclosed by them being occupied by the intestine, 
the nerve-cord, and the ends of the loops of the third pair of 
nephridia, the lateral chambers lodging the lateral parts of 
the ovaries. The median chamber is crossed by strands 
of coelenchyme, the most constant of which is one that forms 
a horizontal partition bounding dorsally a channel (partly 
divided by a median vertical partition) running immediately 
above the nerve-cord. The somatic coelenchyme here forms a 
definite membrane on the ventral side; a splanchnic layer 
invests the ovaries. 
In the anterior trunk region (fig. 7) the vertical septa 
become replaced by oblique septa (of coelenchyme with 
occasional muscular fibres). 
These extend from the middle of the dorsal body-wall, and 
run outwards and downwards, holding the stomach between 
them as they diverge, and are inserted into the lateral parts 
of the ventral surface. There is a continuous somatic layer 
on the ventral side closely related to the ventral longitudinal 
muscles, circumscribing them into two distinct bundles. 
The body-cavity extends through the neck-segment into 
the head (fig. 13 and figs. 1 to 6). Septa of coelenchyme 
with muscular fibres which run nearly transversely separate 
the coelom of the neck-segment from the coelom of the head 
in front {S. 5) and from that of the first trunk-segment behind 
{S. 1). Whether these form complete partitions is doubtful. 
The fact, recorded in my previous paper, that spermatozoa 
occur sometimes in the interior of the head-coelom is not 
conclusive as to the existence of apertures in the septa, since 
the sperms might have been directly injected into the head. 
The neck-coelom, certainly, under certain circumstances, as 
