ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 459 



B. CRYPTOGAMIA. 



Alternation of Generations in Green Plants.* — Mr. J. R. Vaizey is 

 of opinion that comparisons of the life-histories of Coleochsete, (Edogonium, 

 Sphseroplea, Hydrodidyon, Pandorina, Cliara, and the Floridese with that 

 of the lowest mosses show that in all these forms there is virtually an 

 alternation of generations. In the lowest forms the sporophore genera- 

 tion consists of a simple mass of cells produced hy the division of the 

 oospore, and each cell becomes a spore which gives rise to the vegetative 

 body of the oophyte ; in Pandorina, which is the simplest case, the 

 oospore sometimes gives rise directly to a single sexual Pandorina 

 coenobium, or by division to several spores, each of which gives rise to a 

 sexual Pandorina coenobiuni. 



It is suggested that alternation of generations arose from poly- 

 embryony ; if this be true, the sporophy te, as it is more generally known 

 in the mosses and higher plants, is a new body originating among the 

 higher Algas and lower Liverworts not genetically connected with the 

 sexual body ; it follows that the tissues of the sporophyte cannot bo 

 homologous with those of the oophyte, though they may be analogous. 



Thallophytes in Medicinal Solutions.! — Mr. R. G. Eccles states 

 that most educated pharmacists are aware of the fact that aqueous 

 supplies of medicine are subject to pollution during warm weather, even 

 if prepared with what is ordinarily considered scrupulous care as to 

 cleanliness. Unidentified forms of cryptogamic vegetation develope 

 therein from spores supplied by the air, water, drug, or vessel. The 

 author examined various preparations. In a sample of infected dilute 

 phosphoric acid, long, branching, obscurely jointed filaments were the 

 most conspicuous thing in sight. A closer inspection revealed the 

 presence of living micrococci, and of somewhat larger bacteria, probably 

 Bacterium termo. In cinnamon water only bacterial forms were seen, 

 and these evidently decompose the essential oil. In sulpho-cyanate of 

 potassium, carbonate of barium, and phosphate of sodium, organisms 

 containing chlorophyll appear. In solutions of the salts of morphia tho 

 long stringy masses that invade other solutions of alkaloidal salts seldom, 

 if ever, appear. Only motile bacteria and undetermined bacilli were 

 developed. 



Cryptogamia Vascularia. 



Development of the Sporangium of Polypodiaceae.J — Dr. J. 



Kiindig has investigated the history of the development of the sporangium 

 in several species of Polypodiaceae. He finds Polypodium vulgare to 

 differ from all other members of the order in the first division-wall in 

 the epidermal cell which ultimately developes into the sporangium being 

 transverse ; in all the other species examined it is oblique. 



Paraphyses of two different kinds occur in the Polypodiacese : — (1) 

 they spring from the surface of the receptacle among the sporangia, agree- 

 ing in their structure altogether with the trichomes on the under surface 

 of the leaf; (2) from the stalk of the sporangium. In several species of 

 Aspidium, e. g. A. Filix-mas, each sporangium bears one such paraphysis ; 

 while in some other species several spring from each sporangium-stalk, 



* Kep. Brit. Assoc. Adv. Sci., 1887 (1888) pp. 771-2. 

 t Journ. New York Micr. Soc, iv. (1888) pp. 19-28. 

 X Htdwigia, xxviii. (1888) pp. 1-11 (1 pi.). 



