50 Nils Hj. Odhner. 
part of the body (fig. 84), so that here a shallow furrow is obser- 
vable beneath the middle of the body height; or the lower parts of 
the sides are here more prominent than further anteriorly. These — 
features will be reverted to in the sequel. | 
As for the external shape, it was somewhat different in the 
two specimens, owing to their state of contraction. In one of them 
the pharynx was protracted (fig. 77), in the other it was entirely 
involuted (fig. 76), so that the lips occupied a posterior position and 
were withdrawn into the intestine. In this latter specimen the 
posterior end of the animal was acuminated and the cloaca turned 
towards below, whereas in the other specimen the rear end was 
erected, so that the cloaca opened rearwards; this position of the 
cloacal opening must certainly have been secondarily altered by con- 
traction, and the former position may be considered the normal. 
Also the external covering of Gymnomenia justifies its being 
placed apart from all previously known Solenogastres. It lacks the 
spicula, so characteristic of this group, and has only a cuticular 
membrane outside the epidermis. The latter consists of a single 
layer of small crowded cubic or elongated cells (cf. fig. 88), and their 
cuticular membranes are distinctly separated from the adjacent 
ones and in such a manner that the margins form erect edges (cf. 
fig. 81). The whole body surface is thus covered with a fine 
microscopical net-work of cuticular lists (fig. 81), and to this fact 
is due the feeble gleam emitted by the epidermis in reflected light. 
None of the epidermis cells seems to have a secretory function; 
at least none were seen that had acquired the intense tinge 
of haematoxylin characteristic of the spicula-forming cells in, 
for example, Wirenia. The absence of such cells is certainly 
connected with the absence of spicula. In some parts of the body 
the cuticular plates are placed obliquely to the surface. This 
circumstance perhaps represents the first step towards a develop- 
ment of scales; if we imagine that between these cuticula pieces 
spicula-forming cells are developed, we find a correspondence with 
Wirenia and Chaetoderma, where the spicula are covered with 
cuticula membranes on both sides of their base; in these geneta, 
however, as well as in all others, the spicula have become dominant 
over the cuticular plates. 
Only in the ventral furrow does ciliated epithelium exist (fig. — 
88), on the median fold. This fold and the ventral furrow are — 
of sufficient interest for closer examination. In the foremost end of 
