Book Description

Excerpt from The Transactions of the Linnean Society of London, Vol. 9 AllTOG On The have been most valuable and suggestive. Zenkers paper, the first serious attempt to grapple with the internal structure of this group, is full of gross errors of fact and interpretation; and Vernet, the last student of the genus, having dissected but little, has added little to our knowledge. I Avish gratefully to acknowledge much friendly advice from Professors A. Milnes Marshall and G.S. Brady; valuable help in preparing sections from Mr. Walter Langton, Laboratory Assistant at Owens College; and some excellent drawings made by my friend Mr. J.Macpherson, student in Queens College, Cork. For the species my choice has fallen on C.brevicornis, Claus (Das Genus Cijcl. c.p. 32, t.iii. figs.12-17), which I believe to include as a not very distinct variety the later species C.(jigas, CI. (Weitere Mittheil. p.207, figs.1-5); to this it is referred by my friend Prof. G.S. Brady, P.B.S., and my descriptions of the proportions of the appendages c.refer to this solely. The habitat of Cyclops is fresh and brackish water, usually in pools and backwaters. The species under consideration is fairly abundant, and occurs with other species, notably Cserrulatus, C.coronatns, and C.temiicomis, in gatherings made in the neighbourhood of London, Birmingham, Manchester, and Cork (where it occurs in both fresh and brackish water). It is tolerant of captivity, breeding freely in pickle-bottles, c.j but usually in time degenerating in size, though often gaining in transparency. It feeds usually on living animals (e.rj. Rotifers, the youngest of its own species, c.), but will eat dead aquatic animals, and, in the absence of other food, browses on algse, of which its stomach is sometimes full. To obtain specimens in quantities for stocking-purposes, sweeping with a large muslin net may be resorted to; for taking specimens from the jar I use a dipping-tube, much narrowed above to jii event recoil, and bevelled below to make entrance more certain; with this it is easy to catch animals resting against the glass of their receptacle, towards which the bevelled side of the tube is held. The proportion of males to females is very variable: every gathering has some of each. Males are more abundant in autumn and winter. Methods. Examination of the living specimen is of course for many things absolutely necessary. In confinement under the cover undue pressure is avoided by putting under a frond or two of duckweed Lenina). This arrangement has the advantage that by a push at the edge of the cover the Cyclops can be rolled over and over to show in turn back, side, or belly. In this case the legs are usually bent forward, seldom the reverse; but the position may be arranged, before covering, with a needle under the simple microscope, the Cyclops usually shamming dead when touched. Careful management of light and selection of objective are all-important. Points clearly made out imder a wide illuminating ray and a low-angle objective disappear under other conditions, and vice versa. I have found the Abbe condensor invaluable for this work. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.