110 G. HERBERT FOWLER. 
figs. 83—5 the perivisceral space is very large, but with the 
maximum development of the generative organs it becomes 
almost entirely obliterated. 
The alimentary canal (figs. 3—5) commences with a long 
stomodzeum which bends upwards and backwards to about the 
centre of the body ; here it meets with the hypoblastic section 
of the tract, into which it projects as a papilla without direct 
continuity of the embryonic layers. From this point runs 
backwards what is probably the representative of the true 
intestine, terminating blindly at the base of the penis (int.) ; 
it is also continued forwards into the head region (tné'.), and 
sends a third offset upwards and backwards under the dorsal 
wall of the carapace (ind®.) ; all three ceca lying in the median 
plane of the body. Just behind the entrance of the stomodzum 
into the intestine are given off at right angles the hepato- 
pancreatic diverticula, bending outwards and backwards into 
the carapace (in¢*.), and branching into smaller cecal lobes (the 
gland of the left side has of course been removed with that 
half of the carapace in fig. 3). The lining membrane of 
the hepatopancreas and alimentary canal consists throughout 
of well-marked cubical cells, showing no specialisation in any 
particular region. 
The nervous system (coloured black in figs. 3, 5) consists of 
a minute supra-cesophageal mass of transverse nerve-fibres 
devoid of nerve-cells (a curious result of the degraded habit of 
life), of two cireumcesophageal commissures with nerve-cells, 
and of a comparatively thick ventral cord well supplied with 
cells. The latter is apparently not differentiated into ganglia, 
but gives off nerves dorsally to the surrounding tissues. No 
branches of importance are given off to the appendages; no 
eyes or other sense-organs were recognisable. 
The animal is hermaphrodite. The testes (figs. 4, 5) are 
paired, and consist of one or more lobes on each side, lying 
posteriorly in the carapace among the hepatic ceca. The 
diagrammatic figure 4 is taken from a specimen in which the 
generative organs had not reached their maximum develop- 
ment, although the vasa deferentia were charged with appa- 
