ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 607 



the plant are mentioned, which may he influenced by drying, Yiz. : — 

 (1) germination of the zygote ; (2) vegetative growth ; (3) repro- 

 duction and dispersal of the gametes. Several of the common 

 species of Fucoideae were grown also in jars of sea-water, in which, for 

 a certain number of hours daily, the water was removed, in order to 

 reproduce their position with regard to tide-levels. The results of the 

 experiments are described, and the following conclusions are drawn : — 

 1. That the species of seaweeds growing high up on the shore have a 

 power of resisting desiccation, which is not possessed by those growing 

 lower down, and that this power decreases regularly in those species 

 growing towards the lower levels. 2. That the seaweeds which can 

 best resist desiccation grow most slowly, and that those that grow most 

 quickly are the least tolerant of desiccation. In the lower zones, the 

 primary factor is probably rate of growth ; the quickest forms would 

 supersede the others. In the upper zones, the determining factor is 

 tolerance of desiccation. Other possible factors are suggested. 



Sphaeranthera lichenoides.* — F. Heydrich adds further details as 

 to the formation of spores in Sphseranthera lichenoides, on points which 

 he had been obliged previously to leave somewhat obscure. He finds 

 that the sporogenous nucleus emerges from the carpogonium and enters 

 into a row of cells prepared before fertilisation, which He under the 

 procarpia ; the nucleus traverses these cells, which have become 

 disintegrated, and, uniting with another nucleus either at the margin 

 or in the centre, becomes a spore. As in all other Florideae, each 

 procarp is fertilised separately, from which again each single cell 

 undergoes fusion either (1) with the cell of the same filament lying 

 immediately below it ; or (2) with a cell on the neighbouring dichotomy 

 of the same filament ; or (3) with a cell of another filament ; thereby 

 producing spores. Since many such organs occur inclosed in a special 

 cavity, the author forms three divisions on this character : — 1. Coral- 

 lina>Actinococcales with the genera Eleutherospora, Stichospora, and 

 Perispermum. 2. Corallinas-Rhodymeniales with the genera Sporolithon 

 and Paraspora. 3. Corallinas-Cryptonemiales with the genera Sphse- 

 ranthera, StereophyUum, EpiUthon, and Mastophora.. 



Californian Species of Crustaceous Corallines.f — M. B. Nichols 

 continues his contributions to the knowledge of the Californian 

 crustaceous Corallines. In a previous paper (1908), the author gave 

 the results of his study of L it] i nth amnion mediocre Foslie and Nichols, 

 one of the most common of the epiphytic forms. In the present paper 

 he takes up a group of epiphytic forms, including L. marginatum 

 Setchell and Foslie, Lithophyllum macrocarpum f. intermedia, forms of 

 L. past 'nl 'at am and of L. tumidulum. He then discusses briefly some of 

 the characters which have been used as the basis for the separation of 

 the genera Lithothamnion, Lithophyllum, and Melobesia, particularly 

 those characters given by Foslie (1900). Since the latter author has 

 placed the greatest emphasis on the differences in the structure of the 



* Ber. Deutsch. Bot. Gesell., xxvii. (1909) £p. 234-38 (1 pi.). 



t Univ. California Publications (Bot.) iii. (1909) pp. 349-70 (4 pis.). 



