22 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
The nervous system is remarkable for the fact that the two strong 
cords which pass backwards contain the intestinal as well as the pedal 
nerves ; the course taken by them is not the same in V. Leydigi and 
V. Hedleyi, but this is on account of the ditference in the cephalic 
aorta and is of no importance. The distribution of the branches seems 
to the author to show that the whole of the dorsal thickening — the 
notceum — is equivalent to the mantle, and that the pulmonary and anal 
orifices primitively lay much further forwards. 
The tentacles are solid and cannot be invaginated, and the ommato- 
pliores are capable of a considerable amount of forward and backward 
movement. The smooth knob at the end which carries the eye is 
enormously supplied with nerves ; the stalk is quite different to the 
ordinary pulmonate type, being extremely fine, with sharply-marked 
transverse rings ; it recalls in a striking way the tentacles of some 
Auriculacete. The surface of the lower antennae is irregularly papillose, 
and they have a smooth terminal knob, w'ell supplied with nerves. 
This knob contains an orifice which leads into a rounded cavity, from 
the wall of which springs an epithelial cone very rich in nerves. At 
its base there opens a large multicamerate gland which fills uj) almost 
the whole of the tentacle. This organ may be safely regarded as having 
an olfactory function. 
The mucous glands of the skin are no less remarkable, for they are 
not, as is ordinarily the case, unicellular, but are tubular invaginations 
of the epithelium, which are lined by pavement-cells, and into which 
the mucus is emptied from all directions. Differences in arrangement 
are presented by the different species. < 
The foot, finally, has its own remarkable characters ; the arrange- 
ment of the cavernous brain is such that every one of the small solid 
transverse ridges can be swollen out from behind ; the primary vessel 
has not a constant lumen, but has a number of exceedingly powerful 
sphincters, which follow one another as closely as the transverse 
divisions of the foot. 
It is clear that the Vaginulidae are a very remarkable family of tho 
rulmonata, with a large number of characteristic special adaj)tations. 
How these arose we cannot yet say ; their affinities to the Helicida3 and 
their allies are not at all close, nor do they seem to have much to do 
with the Athoracophoridae of the Oriental- Australian province. It is 
most probable that they have a certain though distant affinity with the 
Auriculaceae. 
Neomenia, Proneomenia, and Chaetoderma.* — Mr. G. A. Hansen 
has some notes on these interesting archaic Molluscs. It was stated 
by Hubrecht that Proneomenia Sluiteri had no penis and no gills, but 
P. Sarsii and margaritacea have a penis on either side ; this organ 
appears to be merely a round, hollow tube. As to gills, no such well- 
developed filamentar branchiae are seen as in Neomenia, but there are 
true folds with a lumen, in which blood-corpuscles may be detected. 
The author gives figures of the hinder end of Neomenia, which he hopes 
are more satisfactory than those of Tullberg, and he gives of these a 
detailed description. 
* Bergeus Museums Aarsberetning for 1888 (1889) 12 pp. (1 pi.). 
