Norwegian Solenogastres. 45 
bears a thin cuticula forming the continuation of the main one, 
but externally fringed into cilia. Further the epithelium of the 
furrow, like that of the ventral fold in other Solenogastres, con- 
tains small glandular cells. Towards the rear end of the body 
the ventral furrow tapers and disappears, the epithelium which 
constitutes its covering passing into the general hypodermis; the 
latter, however, projects as a stripe along the median line almost 
in front of, and close to, the cloacal opening. The epithelium 
within the furrow is undoubtedly homologous with that of the 
ventral fold in other forms (cf. comparative section). 
In its inner organization the variety shows complete agree- 
ment with the type. Thus the alimentary canal exhibits the same 
peculiarities (fig. 70). It begins with an atrium the sides and 
roof of which are occupied by the cirri and which leads into a 
pharyngeal tube. The latter in its posterior, somewhat widened, 
portion encloses a conical proboscis (,cöne pharyngien* PRuvoT, 
»Zapienformiger Vorsprung* THIELE), which contains a nartow 
continuation of the digestive canal as well as the salivary ducts, 
which though divided into two ducts posteriorly, open unpaired 
into the apex of the proboscis (fig. 73). The proboscis is followed 
by the narrow thin-walled oesophagus, which has a reflected 
course, running first backwards and then forwards, precisely as 
in the type, till it debouches into the frontal end of the dorsal 
coecum of the intestine. 
From the fact that the rear end of the pharyngeal cone is 
attached to the body wall by means of strong muscles, and that 
it contains circular as well as longitudinal muscles (external and 
internal layers) it may be presumed that the cone is protrusible 
rom its base, and thus represents a proboscis. PRruvor has con- 
sidered this possibility, but gives another interpretation which 
seems to him to furnish an explanation of its morphological 
origin; he says (p. 743): ,je serais disposé å n’y voir qu’une 
exagération de la petite papille salivaire de Proneomenia aglao- 
pheniae“. What militates against this view, however, is the compli- 
cated structure of the cone, which is described by THIELE (1894, 
p. 275) and which shows the following layers (cf. fig. 73) from 
within: (1) ciliated epithelium, (2) circular muscles, (3) long- 
itudinal muscles, (4) parenchyma, probably containing small glan- 
dular cells debouching inwardly and more superficial ones de- 
bouching ,owards the exterior, (5) longitudinal muscles, (6) cir- 
