REPORT ON THE NEMERTEA. 109 



figure at the same time reveals the presence of a conspicuous cuticula covering the free 

 surface of the oesophageal cells. It is not streaked, as the figure erroneously indicates, 

 but homogeneous. On it the cilia are implanted. 



Concerning the behaviour of the intestine in the posterior body-regions of Carinina, 

 nothing can be said, as only anterior fragments were preserved. 



In Eupolia the oesophagus has become more independent of the body-musculature 

 than in Carinina, and in addition to this a separate oesophageal musculature — at least 

 in Eupolia giardii — is present (PI. VI. fig. 9, oe.m). In this oesophageal muscular 

 investment an inner longitudinal and an outer circular layer may be distinguished ; 

 between the latter and the body -wall there is the gelatinous tissue, only locally inter- 

 rupted by the lacunar spaces of the vascular system (in which the nephridia [wp] are 

 suspended), by the dorsal blood-vessel, and by the proboscidian sheath. I mention this, 

 because there is no evidence that this splanchnic musculature has directly evolved out of 

 hypoblastic elements, whereas the evidence that it is enclosed in one continuous stroma 

 with the " somatic" musculature — which in Carinina was the only musculature noticed — 

 and not separated from this by a body-cavity, is very complete. It should, moreover, 

 be remarked that where . this more prominent intestinal musculature makes its appear- 

 ance (certain Schizonemertea, Ewpolia giardii, &c), the internal circular muscular layer of 

 the body- wall of the Carinellidae (8, PI. XL) is no longer present in that -situation. 

 How far these two may be considered as homologous, must be left undecided as long as 

 we do not possess more complete ontogenetical data. This oesophageal musculature 

 was not noticed in all species of Eupolia, and it is certainly curious that it should be 

 present in Eupolia giardii, where the body musculature is so exceptionally thick, and 

 might be expected to serve the purpose of compressing and dilating the oesophageal wall 

 quite as efficiently as we must suppose this body musculature to do in the Carinellidse. 

 M'Intosh, who detected it in Cerebratulus corrugatus, suggests (XXII) that the 

 oesophageal musculature might assist in a partial protrusion of the oesophagus. 



In Eupolia nipponensis and Eupolia australis this special musculature is absent, 

 and we find, on the contrary, a much more considerable development of the deeper cellular 

 layers of the oesophageal wall (PL VII. fig. 12), and a comparatively sharp demarcation 

 between the internal ciliated epithelium (Je) and this thick cellular coating (Jm), this 

 demarcation even sometimes rising to the importance of an apparent basement membrane 

 (B). Between these cells radial fibres, starting from the body musculature, penetrate, and 

 solitary tangential fibres may be observed, but a separate muscular investment of the 

 oesophagus can never be shown to exist. I am not inclined to believe that this difference 

 may be caused by the age or the size of the individual, one of the specimens of Eupolia 

 nipponensis being indeed of considerable size and nearly as thick as Eupolia giardii. 



The same deep cell-layer is met with in the oesophagus of the Schizonemertea 

 (PL XIII. fig. 6), and is no doubt of glandular significance. Generally many of the 



