MOLLUSCA. 
267 
an upper transverse commissure, a lower similar one, and a 
lower portion of ganglia, the anterior of which has been named 
ganglion pedale, the posterior g. viscerate ; none can be re- 
ferred to the sympathetic system. The microscopical structure 
of the nerves and neurilemma is examined, as well as the struc- 
ture of the eyes. The vesiculse containing the otoliths are 
stated to be connected by a peduncle with the upper ganglion, 
but there is no communication with the outer surface of the 
animal. It would appear that the Pulmonata take quantities of 
water into their body by the mouth. 
Keferstein, W. Ueber den feineren Bau der Augen der Lun- 
genschnecken. (Naehricht. Gesellseh. Wiss. und Univers. 
Gottingen, 1865, pp. 237-247.) 
Anatomical description of the eyes of the pulmoniferous mol- 
lusca, with a short review of the accounts of former authors, 
confirming in a remarkable manner that of Swammerdam, and 
identifying the eyes of these mollusks (as regards their ge- 
neral structure) with the simple eyes of the Articulata, espe- 
cially the spiders. Their chief constituents are the sclerotica, 
cornea, a globiform lens, and a retina, formed by fibrous elements 
intermixed with cellulse or granules, and consisting of three 
strata, the middle of whieh is distinguished by a dark pigment, 
the anterior by bacilliform elements. 
Sanders, A. On the anatomy of the generative organs in cer- 
tain Pulmogasteropoda. Quart. Journ. of Microscop. Sc. 
1865, V. pp. 89-96, with pi. 7. 
After an historical introduction the author describes the 
generative glands of Planorbis corneus, Limnceus stagnalis, and 
Helix adspersa. He confirms the opinion that one and the 
same gland, at the same period of time, secretes both zoosperms 
and ova, but that the zoosperms are not formed, as in the Mam- 
mals, in the interior of cells, viz. the vesicles of evolution,^^ 
but are those vesicles of evolution themselves, simply altered in 
shape and attenuated. Following the suggestion of G. H. 
Lewes, he adopts the term dichogamic instead of hermaphro- 
ditic, in order to distinguish this normal occurrence of bisexu- 
alism from the abnormal hermaphroditism of arrested develop- 
ment. 
Binney, W. G. Note on the jaws of Helix. Am. Journ. Conch, i. 
p. 47, with pi. 1. 
The number and disposition of the ribs on the anterior sur- 
face of the jaw varies in different individuals of the same species, 
which is proved by the jaws of nine full-grown specimens of 
Helix tryoni. 
Keferstein, W. Ueber die geographische Verbreitung der 
