SCIENTIFIC SUMMARY. 
233 
referred to our readers will find also an" interesting paper on.tlie liomologies 
of tfie fore and hind extremities. In tliis the author takes up the theory 
of Maclise and also that lately advanced by Mr. St. Geo Mivart, and con- 
fidently rejects both as ingenious but unsatisfactory speculations. 
American Zoologists. — Students of Zoology in this country often require 
to know whether a particular branch of Natural History has received atten- 
tion in America, and if so, by whom This question, so ditficult for the 
beginner, is being solved in a list called the American Naturalist' s Directory, 
which is being published in the Proceedings of the Essex (U.S.) histitute. 
It is arranged under the heading of subjects, and has already made consider- 
able progress. — Vide Proceed. Essex Instit., vol. v. No. v. 
The Anatomy of Helix and Dimax. — A paper was recently read before 
the Microscopical Society w^hich shows the necessity for submitting papers 
to a careful scrutiny before permitting them to be read at the meetings. 
The paper purported to be an original communication detailing the ana- 
tomical differences between certain species of Limax and Helix j but it 
really contained hardly anything which has not been pointed out long ago 
by other observers than its author, Mr. Ed. T. Newton. Indeed, unless we 
are much mistaken, every anatomical feature described by Mr. Newton may 
be found in Moquin-Tandon’s very unreliable pair of volumes, entitled 
Histoire Naturelle des Mollusques terrestres et Jluviatiles. 
New Species of Epistylis. — Mr. Tatem, in a paper on new microscopic 
animals, quotes the following account of two new species of Epistylis re- 
cently discovered by him. Epistylis ovalis. — Zooids two, small colour- 
less, oval, with a contracted raised margin or lip j main stem and branchlets 
long, slender, and of equal thickness. Very rare. On Anacharis. Epistylis 
umhellatus, n. sp, — It is seldom indeed that so perfect an example of this 
elegant form of Epistylis as that figured is met with ; commonly the stalk, 
with some eight or sixteen zooids, more commonly the bare stalk, is alone 
obtainable. So far as I am yet aware, it is found in one ditch only, near 
the wire mills on the Kennet river, near this town (Reading). The zooids, 
which easily become detached, are minute, oval, colourless ,• main stem very 
long, slender, dividing into four branchlets, which again subdivide into 
four each, in an umbellate manner, smooth, and of a light colour. — Micro- 
scopical Transactions, January. 
Origin of Vibrio and Bacterium. — Some very curious experiments, which 
seem to show that yeast is the source of Bacteria, have been made by a 
German lady, Frau Liiders, and are reported in Schultze’s Archie fur Micro- 
scopische Anatomic, Bd. 3, Ht. 3. The experiments consisted in sowing in 
test-glasses, specially prepared, and filled with boiled flesh-water, at the 
moment they were taken from the boiling apparatus, the spores of various 
fungi, taken by means of forceps which had previously been heated to 
redness ; the tubes were then closed with varnish, &c. When the tubes 
thus prepared were placed, immediately after the sowing, into the warm 
bath, a cloudiness was often observed in the fluid in the course of a 
few hours, and within twenty-four hours they always swarmed with 
Vihriones, whilst at the same time the contents of a similar tube, containing 
the same fluid, and prepared in precisely the same way, but into which no 
spores had been introduced, remained unchanged. ^The Vihriones produced 
