54 Nils Hj. Odhner. 
diverticle, however, appears more distinctly. The walls of the intestine 
are lined with a high secretory hepato-pancreatic epithelium except 
the dorsal one, which is constituted of lower cells; further details 
could not be established. Beneath the intestine a ventral blood 
vessel exists, immediately bounded by the intestinal wall and 
the septal muscles, but in communication with the lacunae which 
surround the intestine and the said muscle cords. On both sides of — 
the ventral vessel and round the root of these muscles the pedal 
gland is diffused as a string of glandular cyanophilous cells which 
debouch into the ventral furrow on each side of the median foid. 
Unfortunately we do not know anything about the oecology 
of this interesting Solenogastre. That it was enclosed in a glass 
together with some specimens of Chaetoderma may perhaps be 
interpreted as indicating the same habitat in a muddy bottom. 
The intestine was in both specimens empty which seems to bear 
out the supposition that it feeds, like Chaetoderma, on microscopic 
organisms. 
A greater abundance of material for a closer examination of 
this interesting Solenogastre is highly desirable; but the facts stated 
here are sufficient to show, that Gymnomenia occupies a special 
pesition among these animals. The conclusions which may be 
drawn from it regarding the phylogeny of Solenogastres and Mal- 
Jusca will be dealt with in the following pages. 
COMPARATIVE SECTION. 
GENERAL CONSIDERATIONS ON THE ORGANIZATION 
AND THE RELATIONS OF THE SOLENOGASTRES. 
In the preceding inquiry facts have been presented which seem 
inconsistent with the views prevailing at present on the origin and 
the relations of the Solenogastres. Many of the modern authors 
assume that these animals have originated from higher organized 
molluscs, probably Chiton-like forms, by means of a reduction of 
certain organs, while others have retained ancient features. In 
dealing with Simrothiella I have, however, expressed the opinion 
that the radula of this form may be considered as a specialization 
from a primitive type, and that the assumption of a preceding re- 
duction from the higher type of radula existing in Chitonidae and 
Gastropoda is very improbable. WIrén, in discussing the rela- 
