ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 209 



AVatts, W. W. — Further Notes on Australian Hepatics. 



[List of 44 species.] Op. cit., xxix. (1904) pp. 558-60. 



West, W. — Scapania aspera in West Yorkshire. 



[Frequent in every limestone district.] Naturalist, 1904, p. 379 



Wheldon, J. A. — A gemmiparous Pterigynandrum. 



[Description of P. filiforme var. montanense, a new variety from south-west 

 Switzerland, remarkable for its abundant gemmae.] 



New Bryolog., xxxii. (1905) pp. 7-8. 

 Willia ms, K. S. — Bolivian Mosses. Part I. 



[Treats of Acrocarpi, Andrezea to Funaria, and contains descriptions of 3 new 

 genera and 28 new species.] Bull. New York Bot. Garden. 



iii. (1903) pp. 104-34. 



Zschacke, H. — Vorarbeiten zu einer Moosflora des Herzogtums Anhalt. I. Die 

 Moose des Harzvorlandes. (Preliminary studies for a mossrloru of the Duchy ot 

 Anhalt. I. Mosses of the foot-hills of the Harz.) 



Verh. bot. Vereins Prov. Brandenburg, xlv. (1904) pp. 1-37. 



Thallophyta. 

 Algae. 

 (By E. S. Gepp.) 



Plankton of Three English Rivers.* — P. E. Fritsch continues his 

 algological notes, and the subject of the sixth is a comparison of the 

 plankton of the Cam, at Cambridge, the Trent, at Nottingham, and the 

 Thames. Samples from the first two rivers were taken within a few 

 days of each other in August of last year, and the Thames sample was 

 taken two years previously. A table is given, illustrating the compara- 

 tive constitution of the three rivers. As regards the number of different 

 species in the Trent and the Thames, there is little to choose between 

 the two ; but from the point of view of number of individuals, the 

 author finds that eight species occur commonly, or very commonly in the 

 Thames, whereas in the Trent no species can be called common. The 

 filamentous diatoms are important constituents in both Thames and 

 Trent. A few species, Volvox f/lobator and Ceratium hirwidinella, were 

 found in the Trent only. Bacillaria paradoxa occurs in the Trent, and 

 in the Thames above Teddington, beyond tidal influence. As regards 

 the Cam, the author likens it to a Thames backwater, from its sluggish 

 .stream. He finds that, as in backwaters, the quantity of individuals is 

 muGh greater, although the number of different species (Cam 1C, 

 Thames 30, Trent 32) is markedly less than in a main river like the 

 Thames or Trent. Diatoms are by far the most dominant forms in the 

 Cam. 



Phytoplankton of some Plon Lakes.t — E. Lemmermann continues 

 his studies on the phytoplaukton of these lakes. In the present study 

 he treats of the Great Plon Lake, the Schluen Lake, the Plus Lake, and 

 the small Uklei Lake. In the first he finds there are three periods : 

 I. First Bacillaria period, in which Melosira distans var. Imvissima 

 limn, occurs in masses from January to the end of April ; Diatoma 

 elongatum Ag. in May ; Asterionella gracillima Heib. and Andbcma 



* Ann. Bot., xix.(1905) pp. 163-7. 



t Forsch. Ber. Biol. Stat. Plon., x.(1903) pp. 116-71. 



