ZOOLOGY AXD BOTANY, MICROSCOPY, ETC. 409 



Danish Aerophilous Algae.* — J. B. Petersen publishes a monograph 

 on the Danish aerophilous algfe. By this term he designated alga? which 

 are able to absorb their water supply from the atmosphere, and are able 

 to sustain life during frequent periods of dryness without passing into a 

 resting-stage. He discusses past work on this subject, and the faculty 

 of certain algx to support desiccation ; also experiments of cultivation 

 under conditions of dryness. The main work is divided into two 

 parts, (a) Diatomese, and (b) Chlorophycere. Under Diatomea^ the 

 author divides his remarks under historical, methods, habitat, and mode 

 of life ; and then goes on to the special part, in which he enumerates all 

 the Danish species, giving critical notes and often figures. In his final 

 remarks he gives the conclusions he draws from his work, which are too 

 long to reproduce here in full. The points with which he especially 

 deals are : — 1. Amphibious species, of which he gives a list. 2. Aero- 

 philous diatoms belong to Pennatse, sub-family Raphidete, and are there- 

 fore endowed with the power of locomotion, and can move to damp 

 places during dry periods. 3. He finds that all aerophilous diatoms are 

 of small, sometimes even minute, size. This would, he considers, tend 

 to preserve their life under dry conditions. 



The second part of the work deals with (b) Chlorophycete. Their 

 mode of life is fully discussed, and methods of culture. Then follows a 

 list of all the Danish arophilous species, with critical notes and descrip- 

 tions of new species. 



Diatoms of Vancouver Island.f— L. W. Bailey and A. H. Mackay 

 publish the first record of the diatoms of the Pacific coast of Canada. 

 The collections come from the vicinity of the Biological Station at 

 Nanaimo. The authors discuss the planktonic species, genus by genus, 

 and give a list of the non-planktonic forms, and show also which species 

 are common to the Pacific and Atlantic coasts of Canada. They also- 

 provide an enumeration of all the species and varieties, as determined 

 by Bailey, Mackay, and 0. Kendall, indicating briefly the length and 

 breadth of each in its valval or zonal aspect, the degree of fineness of 

 sculpture, and other characters. Provisional new species and varieties 

 are suggested. 



Saprophytism of Enteromorpha.|— E. Hayren describes the sapro- 

 phytic habits of certain species of Enteromorpha. In the harbour region 

 of Helsingfors he found in late summer and autumn a close, well- 

 developed mat of algge composed almost entirely of £J. intestinalis, 

 E. flexuosa, and E. crinita. It extends from the level of mid-tide to a 

 depth of 2-3 '5 dm., and is laid bare in the autumn low tides. This 

 mat arises from the influx of drainage into the sea. All stages are 

 found from polysaprobic to pure water. In Tolo Bay, near a great 

 drain-opening, there is a polysaprobic zone {Beggiatoa, Spirilla, and a 



* Kgl. Dansk. Yidensk. Selsk. Skrift., ser. 7, xii. No. 7 (1915) pp. 272-380 (4 pis. 

 and figs.). 



t Trans. Boy. Soc. Canada, ser. 3, ix. sect. 4 (1915) pp. 141-73. 



X INIedd. Soc. Fauna et Flora fennica, xxxvi. (1910) pp. 157-61. See also Bot. 

 Centralbl, cxxxi. (1916) pp. 400-1. 



Aug. 16th, 1916 2 F 



