168 HICK : VOLVOX IN YORKSHIRE. 
may yet be found at higher elevations. From the numerous facts 
which have come under my notice indeed, I am inclined to think 
that elevation has far less to do with the distribution of Volvox than 
the nature of the pond and its isser Sects surroundings. 
L ConpiTions.— The i mediate surroundings or the local 
ish 
ssrs. Crossland and Carnell, of Halifax, respecting the pond at 
Salterhebble. 
Mr. Crossland writes :—‘ The altitude of the pond . . . is about 
650 ft. above sea-level. It appears to have at some time been 
excavated on the side of the hill. It is situated a little above the 
outcrop of the hard-bed coal belonging to the lower coal measures. 
The hillside faces W.S.W. The pond is fed bya spring. There are 
three large old thorn trees on the margin—two on the south and one 
on the east—also Glyceria fluitans, Lotus uliginosus, and a few other 
water-loving plants. There is plenty of Cadiitriche, from the 
washings of which we get Bulbochete and Coleochete, and of 
Desmids, Doctdium, Staurastrum, Cosmaritum, and  Closterium. 
I don’t remember having seen any Zemna. Fish were put in a few 
years ago by the farmer.’ 
Mr. Carnell writes:—‘The pond is not a very large one—say 
about 30 yds. by 15 yds.—and will be six or eight feet deep. The 
edges and greater part of the bottom are covered with Starwort, etc., 
and it contains some small Chub and Perch. There is no 
perceptible inlet or outlet of water—probably it is supplied by some 
top spring.’ 
In addition to the points included in these accounts, a few 
particulars have been obtained in one or two isolated cases as 
regards the temperature of the ponds and the depth at which 
Volvox is found in bright and cloudy weather respectively. The 
temperature observations I am disposed to regard as of great 
importance, and as the evidence of its influence on the well-being of 
Volvox is somewhat conflicting, it is to be hoped that special 
attention will be paid to it in the future. The accounts of the effect 
of wind are also wanting in uniformity, the plants being driven, 
according to some, to the far side of the pond, while according to 
others they remain on the windward side. These discrepancies may 
Naturalist, 
