273 



animals referred to are easily obtained, for one can hardly 

 examine a Daphnia, Cyclops^ or other aquatic creature, to 

 say nothing of the water-weeds, without finding numerous 

 specimens. And after getting the material to work upon, all 

 that is necessary in this case is the skilled use of the highest 

 powers with the best possible illumination, and a little care 

 in supplying the animals with some harmless colouring-matter 

 as food. It is really quite remarkable, when there is so much 

 valuable work to be done, that so many expert microscopists, 

 with the finest lenses and apparatus at their disposal, shoidd 

 be content to gaze for ever at mounted diatom valves and 

 other " test objects." Probably it is that they do not know 

 what wants doing. Such a book as the present should give 

 them plenty of choice of subject, and we therefore heartily 

 recommend it, not onlv to students of all branches of the 

 Protozoa, but also to the amateur high-power mici-oscopist who 

 wants to use his skill upon something that will yield results 

 of real value to biological science. D. J. S. 



British Tyroglyphidae. By A. D. Michael, F.L.S., F.Z.S., 

 F.R.M.S., etc. Vol. I. 8| x 5| in., xiii -f 291 pages, 

 22 plates. London, 1901 : Ray Society. 



This handsome work, which cannot fail to add greatly to 

 the already world-wide reputation of our distinguished Vice- 

 President, is one which will doubtless prove of the greatest 

 service to all who are interested in the studies of the Acarina, 

 concerning which the available literature has hitherto been 

 somewhat scattered and imperfect, as well as being — with the 

 exception of Mr. Michael's own papers in the Journals of the 

 R.M.S., Q.M.C, and the Linnean and Zoological Societies — 

 the production of foreign writers. In the volume before us, 

 and in that which is to follow, British species are alone dealt 

 with ; but the distribution of these minute creatures is so 

 universal that perhaps not many genera will escape mention. 

 The introductory chapter will probably be the one of most 

 interest to the general reader, describing as it does, in popular 

 language, the general characters and habits of this innumerable 



