ZOOLOGY AND BOTANY, .MICROSCOPY, ETC. 771 



other methods failed or were, for any reason, not available. The 

 method is. however, complicated by the necessity of paying attention to 

 colour-intensity, fibre-thickness, and orientation. Even in comparison 

 with samples these considerations must be observed. The authors give 

 a long list of their results, their colour-names being made to correspond 

 with those used in Gr. Schnltz' " Tabellarischen Ubersicht der im 

 Handel befindlichen Kiinstlichen organischen Farbstoffe " (Berlin, 

 1902). 



Examination in Microscopy.* — r]xamination questions upon almost 

 every subject are now in vogue ; then why not upon Microscopy ? 

 Here are two with which to begin : — 



1. With a Ross 4 in. (actually a 2f of "085 N.A.) resolve Grayson's 

 10,000 band, using artificial light from a paraffin lamp with a h in. wick. 



2. "With the same illumination and a Zeiss aa, resolve Grayson's 

 20,000 band. 



A light-filter may be nsed in answering both these questions, and 

 the time allowed for this paper is one week. 



Resolutions with low powers sound charmingly simple ; but these 

 two resolutions will not be ' accomplished by anyone who is not well up 

 in microscopy. Those who do not wish to go in for the paper may do 

 worse than occupy some of the coming winter evenings in trying to 

 solve these questions, for facility in microscopical manipulation, as in 

 everything else, can only be acquired by practice. — E. M. Nelson. 



Quekett Microscopical Club. — The 168th Ordinary Meeting was 

 held on October 25, at 20 Hanover Square, W., the President, Professor 

 E. A. Minchin, M.A. F.Z.S., in the chair. A paper on "Some New 

 African Species of Volvox," by Professor G. S. West, M.A., D.Sc, F.L.S., 

 was read by Mr. C. F. Rousselet, F.R.M.S. The first of the new 

 species, Volvox Roussehti sp. n., was collected by Mr. C. F. Rousselet 

 from a pool near Gwaai station in Rhodesia in 1905. The diagnostic 

 features of this new species are, the enormous number of the cells, from 

 about 25,000 to more than 50,000, constituting the colony, and the 

 density of their arrangement. V. africanus sp. n. was obtained by 

 Mi'. R. T. Leiper from the Albert Nyanza in 1907. The form is close 

 to V. aureus, but differs in the form uf the vegetative (asexual) 

 colonies, in the great development and compression of the daughter- 

 colonies before they are set free, and in the fact that three, and often 

 four, generations of colonies always appear to be well marked. A 

 paper on "Two New Species of Gassidulina" contributed by Mr. H. 

 Sidebottom, was read by Mr. A. Earland. These are Cassiiltdina 

 elegans sp. n. and O. decorata sp. n. Both forms were obtained from 

 1 1. M.S. ' Waterwitch,' South-west Pacific, station 159, and the second 

 form also at station 256. Mr. 0. D. Soar, F.R.M.S., read "A Con- 

 tribution to the List of Hydrachnidie found in the East African Lakes." 

 The contents of three tubes had been examined. These had been 

 collected from Victoria Nyanza, Tanganyika, and Nyassa respectively. 

 From the Victoria Nyanza tube only one species was identified, 

 Unionicula figuralis Koch. From Lake Tanganyika six forms were 



* English Mechanic, xcii. (1910) p. 297. 



