©) 
or 
Fig. 8). A more full-grown spieule in which the bag fits more tightly round the base. 
s, bandn, as in fig. 7. 
m. cellular matrix of the integument. 
s. very young spicule still jmbedded in the cellular matrix. 
Fig. 9. Outline of the posterior extremity of the body, seen from above. 
s. a small opening in the integument. 
Fig. 10. This opening more strongly magnified. Radial folds of the integu- 
ment surround it. 
Fig. 11. Longitudinal section through this opening. 
S. the opening. 
e. the epithelium at the bottom of it. 
N. nerve-branch running towards this epithelium. 
M. muscular layer of the bodywall. 
I. integument. 
Fig. 12. Schematic longitudinal section through the anterior extremity ofthe body. 
OÖ. mouth. 
P. pharyngeal cavity. 
B. intestine. 
F. foot. 
t. lip-like fold inside the mouth. 
f. accessory folds between this and the mouth. 
r. common opening of the cavity for the radula and of the sali- 
vary glands into the pharynx. 
c. longitudinal coecum of the intestine bent forwards over the 
pharynx. 
a bloodsinus. 
vs. ventral 
g. anterior foot-gland. 
Fig. 15. The same through the posterior extremity of-the body. 
B, F, dsand vs, as in fig. 12. 
h. the heart. 
1) It is indeed curious to notice how close the resemblance is between 
Beincke's figures of the integument and spicules of Chitonellus fasciatus (25, 
Pl. 22, figs. 21, 24 e.a.) and our figures 7, S and 23. There too the spicules 
are formed in the deeper layers, gradually and passively carried outwards by 
the increase in thickness of the cuticula and connected with the cellular matrix 
by a string-like funicle. Those that arrive at the exterior surface are often 
broken off. This resemblance is the more remarkable as in Neomenia, which 
in other respects is more closely related to Proneomenia, a different constitu- 
tion of the integument obtains. So along this line ‚of enquiry the connecting 
link between the two orders of the Amphineura is once more strengthened. 
Husxecut, Proneomenia sluiteri. e 
