PROCEEDINGS OF SCIENTIFIC SOCIETIES. 263 
disease, avd not from the above acquired habit. He, however, supports 
Mr. Crotch’s statements as to the number and kinds of predacious birds 
and mammals which, as enemies, devour the Lemmings wholesale, and 
also that, by a perversion of taste or otherwise, both domestic cattle and 
Reindeer destroy them. Their occasional enormous increase in numbers 
our Scandinavian field-naturalist holds is owing to periodic prolific years, 
to the facility of rearing their young, and to their remarkably easy pro- 
creative faculty. Parallel instances among other groups of animals—for 
instance, unusual swarms of butterflies, locusts, &c.— are well known, 
though as to the true reason of such departures in number, &c., much that 
is averred is only conjectural. Coincident with the notable years of the 
Lemming's migrations, the increase above the normal numbers of rats, 
mice, shrews, and even the grouse tribe, have been recorded. Mr. Collett 
affirms that the Lemmings travel chiefly in the direction of the valleys, 
and not constantly due west, as has been asserted: their great movements 
en masse are chiefly nocturnal. He is inclined to question Mr. Crotch’s 
theory of a hereditary search for a lost “ miocene Atlantis,” and is rather of 
opinion that, in accounting for the periodical excess of multiplication and 
migratory impulse, a physiological necessity impels them; the nature of 
this is at present beyond our power to explain rationally and with certainty. 
A further contribution to the Natural History of Swine, by Professor 
Rolleston, was read in abstract, this paper forming an appendix to that 
previously brought under the notice of the Society. The additional infor- 
mation is in the main confirmatory of the views already expressed by the 
author ; but several important facts,—to wit, relative to the striping of the 
young of Sus celebensis and S. verrucosus, according to Dr. A. B. Meyer,— 
with information from other naturalists on kindred points, necessarily cause 
a modification of the conclusions formerly drawn. 
The following botanical papers were read or referred to in abstract :— 
“On a Collection of Ferns made by Miss Gilpin in the Interior of Mada- 
gascar,” by Mr. J. G. Baker. ‘‘ Freshwater Alge of the Cape of Good Hope,” 
by Prof. Reinsch. “On South-African Liverworts (Hepatica),” by Mr. W. 
Mitten. “On some New Irish Lichens,” by the Rev. W. A. Leighton. 
April 19, 1877.—Grorce Beytuam, Hsq., F.R.S., in the chair. 
A paper was read by Dr. Francis Day, “ On the Geographical Distribution 
of Indian Fresh-water Fishes” (Part II. The Siduride). These, the so-called 
Sheat-fishes, form a large family amongst the Physostomi of Asia. Mostly 
scaleless, their mouths are provided with sensitive feelers, which, serving as 
organs of touch, assist them when seeking for their prey in turbid waters. 
Vision in such localities would be but of slight service, and, as might be 
anticipated, their eyes are comparatively small, whilst with advancing age 
these organs become atrophied, or at least do not incréase in the same ratio 
