Jan., 1890. 
REPORTS OF SOCIETIES. 
28 
study was so advantageous for this purpose as natural science.— 
November 25th. Mr. J. Betteridge presented specimens of the 
common heron, Ardea cinerea , and wheat-ear, Saxicola cenanthe, to the 
collection of the society, for which hearty thanks were passed. 
Mr. J. Collins then read a paper on “ Filamentous Fresh-water Algae.” 
The writer referred to some of the benefits students of botany and 
biology derive from a careful study of these minute plants, their 
simple cellular structure demonstrating very beautifully the manner in 
which plants grow by cell-division. One of the greatest difficulties to 
their study is the lack of literature on the subject, a good work, at a 
moderate price, being much needed; the only one we have is beyond 
the means of many working naturalists. The various modes of 
reproduction, both sexual and asexual, were referred to at some length, 
special consideration being given to the very elaborate method of 
sexual reproduction. Several species were mentioned for their extreme 
beauty. The habitats of algae were very variable, such as damp 
ground, stagnant ponds, clear streams and cascades. The paper closed 
with an account of the important position these plants hold in the 
organic world as purifiers of water, &c. A number of species were 
shown under microscopes, and a collection of drawings handed round. 
—December 2nd. Mr. T. H. Waller, B.A., B.Sc., gave a description of 
the various rock sections he presented to the cabinet of the society. 
He said they had been specially chosen to show the different types of 
rock structure. One, a limestone of Silurian age, showed foram- 
inifera ; the junction of granite and schist was well seen in a specimen 
of Cornish granite ; the other slides included porphyritic rook from 
Whitby, Mexican quartz, containing fluid carbonic acid and water in 
cavities, rocheand bluestone from Rowley Regis, showing their identity. 
OXFORD NATURAL HISTORY SOCIETY.—December 3rd. 
The President in the chair. Mr. W. Warde Fowler gave a very 
interesting account of the habits of two of the warblers observed by 
him in the Alps for several years past. The first of these was the 
Marsh Warbler (recently recognised as an Engligh bird), which shows 
an almost absolute identity in form and plumage with another species, 
the Reed Warbler, so that dead specimens of the two are indis¬ 
tinguishable, while in habit, gesture, song, nest, and eggs, the two 
species are quite distinct, and never interbreed. From this a con¬ 
clusion was suggested that plumage ought to rank less highly as a 
specific character than it commonly does. Mr. Fowler then described 
the habits of Bonelli’s Warbler, chiefly observed by him on the lower 
thousand feet of the mountains bordering the Hash Thai. This 
species is closely allied to the Wood Warbler, and is considered likely 
to push its way into England, as its European range has been observed 
to be extending northward, and has been traced from Italy to northern 
France. In the discussion which followed, stress was laid on the fact 
of permanency of habit often outlasting structural change, and, among 
other instances adduced, was that of the now wingless Apteryx, which 
still, at rest, endeavours to tuck its head under its rudiment of wing. 
Professor A. H. Green exhibited and explained a model showing in 
action the manner in which the products of denudation are deposited 
in sedimentary strata. Dry sand, composed of grains of varied sizes, 
and clay were mixed together in a pan. This pan communicated by a 
sloping gutter with a long shallow pan filled with water. Upon the 
mixture water was poured from a rose to imitate the action of rain, and 
the mingled mud and sand, being carried down by the gutter into the 
trough, was seen after an interval to have sorted itself into deposits, 
in progressive order from the mouth of the trough, of coarse sand, 
finer grained sand, mixed sand and clay, and finally impalpable mud. 
