ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 929 



solution of pliosplioric acid, germinated ; while in a mixture of starch- 

 paste and solution of diastase with 4 per cent, of that acid the ferment 

 lost its activity. 



Since, therefore, these various substances do not always act in the 

 same way on living vegetable cells on the one hand, and on ferments 

 on the other hand, the author concludes that the vital processes depend 

 on quite other fundamental causes than on the presence of processes 

 of fermentation. 



The author confirms the observation of Nasse that the presence 

 of carbonic acid promotes in a remarkable manner the process of 

 fermentation. 



Algae. 



Algological Notes.* — The second part of Bornet and Thuret's 

 'Notes algologiques ' contains descriptions of a new species of 

 Monostroma and of several new or little-known Florideee, as Ptilo- 

 thamnium pluma Thur., SpondylotJiarnnmm multifidum Ng., &c., &c. 

 But it treats chiefly of the Nostochinete, and contains an entire 

 rearrangement of the species of Nostoc and Sci/tonema. The forma- 

 tion and development of the spores are described in numerous 

 species of Nostoc, Nodidaria, and GloeotricMa, and of the hormogonia 

 in these forms, in Scytonema, Lynghya, CalotJirix, Pledonema, Bivularia, 

 and Isacfis. The most important processes are remarkably uniform 

 within the family. The authors also give fuller descriptions than 

 have hitherto been published of Mia-ochcete, Fischera, Hormacfis, and 

 other genera. The last-named genus is interesting as uniting the 

 characters of Nostoc and Bivularia. The plates are remarkably 

 carefully and accurately executed. 



Sexual Reproduction of Phaeosporeae.f — G. Berthold describes a 

 process of conjugation in Ectocarims siliculosiis and Scytosiphon lomen- 

 tarium. The swarmspores, which are found in pluriloeular sporangia, 

 were cultivated in a moist chamber. Some came to rest earlier than 

 others, losing their cilia ; these are female, otherwise completely re- 

 sembling the male in both size and form. When come to rest, they 

 exercise a powerful attraction on the male swarmspores, which move 

 round them in a dense mass until one of them coalesces with the 

 female ; and the impregnated swarmspore clothes itself with a cell- 

 wall. It is noteworthy that the female swarmspore is in a receptive 

 condition only for a few minutes ; if it is not impregnated during this 

 time, it clothes itself with a cell- wall and germinates without impreg- 

 nation. But the fertilized swarmspores germinate earKer than those 

 that have not been fertilized. The male swarmspores which have not 

 conjugated also come to rest and germinate ; but the resulting indivi- 

 duals are weakly, and soon perish. The fertilized swarmspores gave 

 rise to filaments which bore both pluriloeular and unilocular sporangia, 

 the latter being possibly the immediate result of impregnation. 



In Ectocaiyus pusillus and Girardia sphacelarioides the author 



* Bornet, E., and Thuret, G., ' Notes algologiques.' Fasc. 2. (Paris, 1880.) 

 t MT. Zool. Station Neapel, ii. (1881) 1 pi. See Bot. Ztg., xxxix. (1881) 

 p. 290. 



Ser. 2.— \Qh. I. 3 Q 



