ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 721 



Sexual Reproduction in Stigeoclonium.* — A. Pascher has studied 

 this subject and made observations on the living plants for the last two 

 years. He finds that in some points his conclusions differ from those of 

 former authors, and he sums up his results as follows : There is a general 

 formation of macrozoospores which have four cilia and a direct germina- 

 tion. The microzoospores are formed like the macrozoospores from the 

 vegetative condition : they are 4-ciliated, and before germination they 

 go through a resting condition of often very short duration. In rare 

 cases they copulate. Bi-ciliated zoospores are formed from the resting 

 spores (akinetas or palmella condition). These germinate directly, and 

 it has been stated that copulation occurs among them. The formation 

 of bi-ciliated gametae from vegetative cells has been asserted, but the 

 author considers that sufficient proof is wanting. The aplanospores are 

 modifications of microzoospores. 



Brown Colouring Matter in Algae.f— H. Molisch has made ex- 

 periments in connection with the brown colouring matter of the Phseo- 

 phyceae and Diatoms, and he finds that the substance "phycophain" 

 does not exist in the living cell at all as has been generally believed, 

 but is formed from a chromogen after death. Phaeophyll, on the other 

 hand, exists in the living chromatophore, and is easily converted into 

 common chlorophyll. This fact holds good both in Phaaophyceaa and 

 in Diatomaceae. The author finds that he can convert ordinary chloro- 

 phyll by chemical reagents into a brown colouring matter, and this in 

 its turn shortly changes back to alkali-chlorophyll. Comparisons are 

 made between the brown colouring matter of these groups of algae and 

 that discovered by Schimper in the living chromoplasts of Neottia nidus- 

 avis. Leucocyanin has been found in the chromatophores of Phaeophyceae 

 and Diatomaceae, together with carotin and chlorophyll. The presence 

 of leucocyanin causes the algas to turn blue-green in a solution of 2 p.c. 

 hydrochloric acid. 



Spore Formation in Biddulphia mobiliensis.J — P. Bergon publishes 

 some new observations on this process as it occurs in B. mobiliensis. 

 During quiet days of the winters of 1902-3-4 he noticed a tendency to 

 form internal spores, and he describes the manner of their formation. 

 The nucleus divides and also the cell-contents. Two membranes are 

 formed, the external convex surfaces of which are in contact at their 

 extreme point. Then follows successive division of the nucleus and cell 

 contents into 2, 4, 8, 16, or more, spores. He noticed that the spores of 

 one and the same cell did not all divide in the same manner, and were 

 thus of different sizes and even varied in number. Nevertheless the 

 total number of spores in each daughter-cell was either 32 or 64 when 

 the division was complete. These spores became motile inside the 

 daughter-cells, and this motility was even seen to begin during the divi- 

 sion of 16-32 spores. The movement is rotary ; the spores have two 

 long cilia and a spheroidal swelling at the free end. The author then 

 describes in detail certain phenomena connected with spore-formation 



* Flora, xcv. (1905) pp. 95-107 (2 figs, in text). 

 t Bot. Zeit., lxiii. (1905) pp. 131-44. 

 \ Microgr. Prep., xiii. (1905) fasc. 1, 2. 



Bee. 20th, 1905 3 c 



