616 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Batrachians. This consists either in injecting a highly concentrated 
solution of metliylen-blue into the veins of an adult, or of making a 
very dilute solution in the sea-water in which the embryos of Cephalo- 
pods are living. The latter gradually accumulate the colouring matter 
in their integument without any apparent injury to the animal. The 
injection of a concentrated solution into an adult very rapidly shows up 
the cutaneous nervous network which is peculiar to the chromatophores. 
The terminal fibres of the nerves may be seen ending in a swelling in 
each of these organs. The immersion of embryos in coloured sea-water 
rapidly leads to the appearance of the sinuous lines of the special 
cells ; the network of nerves soon becomes evident, and their termina- 
tions are seen even better than in the adult. If the staining be deeper 
the nerve-centres which preside over the movements of the chromatophore 
become very sharply coloured. These centres are the pallial ganglia, 
which are united by a transverse commissure which has never yet been 
described. 
The author has investigated the cutaneous glands of Eledone moscliata ; 
he finds that the skin of this Cephalopod contains very large mucous 
epithelial cells in which there is a large droplet of fatty matter, which 
is the “ musk.” The contents of these cells are probably a mixture of 
fatty and volatile matters which are soluble in ether ; the residue 
obtained dry in small quantities only is of a yellowish colour and 
strongly odorous. 
Finally, the author discusses the cutaneous ink-secreting organs of 
Nautilus. As a Nautilus grows it comes in contact by its back with a 
part of the shell which has been for a more or less long time exposed to 
shocks from without, and has become rugous. It covers this part with a 
black varnish secreted by the edge of the mantle. This varnish is itself, 
some time later, covered by the nacre which is also secreted by the 
mantle. The part of the mantle which is charged with the deposit of 
varnish is the superficial cutaneous epithelium, modified in a special 
region for this secretion. The cells of this region are caliciform and 
curved ; they secrete very fine black granulations which accumulate 
in the cuplike part, and are deposited in the successive zones of the 
shell with which they come into direct contact by their large orifice. 
y. Gastropoda. 
New Classification of Helices.* — Mr. H. A. Pilsbry invites considera- 
tion of a classification of the Helicoid snails which is, he says, essentially 
modern and essentially original. In dissecting the male generative 
organs of snails, note should be made of (1) the shape of the penis, 
(2) the presence or absence of internal papilla and external appendix, 
(3) presence or absence of flagellum or epiphallus, and (4) the point of 
insertion of the retractor muscle and of the vas deferens. In the female 
system the presence or absence and the form of dart-sacs, darts, mucous 
glands, should be noticed, as well as the length of the spermathecal 
duct, the form and position of the caeca of the ovotestis, and, finally, 
whether the right eye-peduncle is retracted between the branches of the 
genitalia or to the left side. 
With regard to the value of the jaw as a basis for classification there 
* Proc. Acad. Philadelphia, 1802, pp. 387-404 (1 fig.). 
