A CONTRIBUTION TO THE ANNELIDA. 65 
vessels above the latter channel (which lies over the intestine) 
takes place, so that a large mass, composed apparently of thick 
striated walls round a central lumen, is soon formed. It is 
difficult to say what this is, though it possibly may be a 
specially contractile region of the vessel. It is shown in its 
fully-developed condition in Pl. 7, fig.5,v.g. It then splits 
into two trunks which gradually separate from each other as 
we proceed forward, but they always preserve a dorsal position 
to the duodenal gut, stomach, and proboscis. They diminish 
in size as they go forward, but they retain the same structure 
and contractility. Their mode of termination could not be 
ascertained. 
The structure and arrangement of these parts would point to 
their connection with the vascular system, but as no vessel 
contains blood, and as their structure differs from the distended 
trunks, some doubt exists. Their highly contractile condition 
may be associated with the functions of the proboscis, which, 
as formerly shown, has large blood-vessels inferiorly. 
Segmental Organs (Nephridia).—Schmarda does not 
refer to these organs, but Ehlers describes them in his form as 
reaching to the twentieth segment. They lie under the dorsal 
wall of the body, and have their external openings in the 
median line between the branchiz. Lach is in the form of an 
elongated bifid tube, extending over two or three segments. 
The two inner openings are trumpet-shaped, with orange pig- 
ment and internal cilia. The only structures observed in the 
sections of E. foliosa are the bifid vessels passing over the 
proboscidian region from the single dorsal tube as described 
above, and such would appear to pertain to another system. 
Generative Elements.—Schmarda describes the ovaries 
as funnels or tubes with a blood-vessel in the middle. These 
tubes end in an oviduct which opens near the vent or near the 
inner branchie. The specimens examined by Ehlers had no 
generative elements. These elements in E. foliosa occur in 
the perivisceral space around the alimentary canal, and at the 
bases of the feet (PI. 6, fig. 1, ov., and Pl. 7, figs. 5 and 6,9. p.). 
In the male the dense masses of sperm-cells are often arranged 
voL. 36, PART 1.—NEW SER. E 
