HENRY LAWSON, M.D., M.R.C.P., F.R.M.S., THE MONTHLY MICROSCOPICAL JOURNAL. JULY 1, 1876. I.-On the Rotifer Conochilus volvox. (Read before the ROYAL MICROSCOPICAL SOCIETY, June 7, 1876.) PLATE CXLIII. FEW microscopic objects have been so much gazed at during the last dozen years as Conochilus volvox; scarcely a single scientific soirée, where the microscope has figured, has failed in a supply of their living crystal spheres; yet it would be difficult to mention a minute creature of any attractiveness which has been so little studied and is so little known. It is the object of the present paper, in part, to supply the omission, and to piece together, in a manner as disjointed as may be, the notes made on this beautiful rotifer, at somewhat wide intervals during the last seven years. My early gatherings were made at Hampstead Heath in 1868, but lately this locality has failed me, and by the assistance of my friend, Mr. F. Oxley (who is the best collector I know), a fairly continuous supply has been kept up, mainly from the ponds about Snaresbrook. Now a careful scrutiny of the very first gathering revealed the fact that, judged by the rules of symmetry as applied to the Melicertans (among which, latter-day observers class Conochilus), this rotifer has its leading features entirely dislocated. The most striking peculiarities are found in and about the head; but before going into particulars, it may be well to note what authority says about it. Ehrenberg tells us: "The frontal region EXPLANATION OF PLATE CXLIII. FIG. 1.-Diagram sketch of head of a Melicertan (Limnias). 2.-Diagram sketch of head of female Conochilus. 3.-Group of Conochilus volvox (female), × about 300. 4.-Male 7.-Ephippial egg VOL. XVI. |