ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 611 



H. Wilsoni he regards as a natural hybrid between H. Sendtneri and 



H. lycopodioides, and gives reasons for this view ; for instance, he has 

 never gathered H. Wilsoni except in pools where H. Sendtneri and 

 H. lycopodioides grow together. In conclusion, he appends a list of 

 Harpidia ad tinea, based upon the work of Sanio, Renauld, and Warnstorf, 

 the main features of which (apart from numerous varieties and forms) 

 are as follows : — 1. Hypnum polycarpon Bland. (H. Kneiffii Schimp.) ; 

 (2) H. simplicissimum Warnst. ; (3) H. subaduncam Warnst. ; (4) H. 

 pseudofluitans Klinggr. ; (5) H. Barbeyi Ren. ; (6) H. capillifolium 

 Warnst. ; (7) H. Sendtneri Schimp. ; (7a) H. Wilsoni Schimp. ; (8) 

 H. lycopodioides Schwaegr. ; (9) H. latinerve Arnell. 



Introductory Study of the Muscinese.* — T. H. Russell has pub- 

 lished a book on Mosses and Liverworts : an introduction to their study, 

 with hints as to their collection and preservation. He first treats of the 

 mosses, giving some of the more generally interesting facts concerning 

 them, with a sketch of their life-history and various modes of reproduc- 

 duction. He then treats of the hepatics on the same lines ; and in 

 chapter iv. he goes carefully into the questions of the collection, ex- 

 amination, and preservation of specimens, describing the most appropriate 

 apparatus to use, and how to make it ; and giving' explicit instructions 

 for the preparation of Microscope slides, with hints as to how the many 

 pitfalls that beset the beginner may be avoided. 



Luminosity of Schistostega.f — W. West expresses the opinion that 

 the luminosity of Schistostega osmundacea, which always grows in 

 sparsely lighted caverns, is due to the peculiar shape of the cells of the 

 protonema, which are convex above and conical below. An incident ray 

 of light is first refracted upon entering the cell, then reflected across the 

 cone, again reflected, and finally refracted upon emergence, so that some 

 of the light passes back along the path by which it approached the cell ; 

 and the modification which the light has undergone in the protonemal 

 cells accounts for the strange character of the luminosity. 



British Hepaticse.J — B. Cockburn publishes a short note on the 

 distribution of Pallavicinia hibernica and the rare and inconspicuous 

 Petalophyllum Ralfsii in Britain, and the conditions under which they 

 occur, namely, in salt marshes near the sea. The two plants sometimes 

 grow together. 



W. Evans § gives an account of the distribution of the species of the 

 genus Riccia in the reservoirs around Edinburgh in 1905, in the 

 autumn, when the level of the water was remarkably low. He visited 

 fifteen reservoirs, and found R.sorocarpa to be present in all. R.glauca 

 occurred in eight, R. crystalUna in five, R. Lescuriana in three, and 

 R. fluitans f . canaliculMa in two. R. crystal I i mi was previously unknown 



* London : Sampson Low, Marston, and Co. (1908) xiv. and 200 pp. (10 pis.). 



t Naturalist, No. 606 (1907) p. 256. 



% Trans. Proc. Bot. Soc. Edinburgh, xxiii. (1907) pp. 279-80. 



§ Tom. cit., pp. 2S5-7 (1 pi.). 



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