546 SUMMABY OF CURRENT RESEARCHES RELATING TO 



The author describes in detail the development under these 

 circumstances of nine different filamentous species ; and arrives at the 

 following general conclusions: — (1) That the relationship between 

 the Schizophycese and the Schizomycetes is much closer than has 

 hitherto been generally believed, confirming the classification adopted 

 by Cohn and Sachs of including these two families in the same group 

 of Schizophyta. (2) That a new impulse is thus given to the study 

 of the SchizophyceEe. (3) That the formation of zoogloea is a more 

 widely spread phenomenon than has hitherto been supposed, as is 

 illustrated in Cienkowski's observations on TJloihrix, Cylindrocapsa, 

 and Gloeothamnion. The results obtained tend also to the conclusion 

 that many other members of the group of Chroococcaceae are merely 

 stages of development of filamentous Schizophyceee. 



Motion of Diatoms. — Prof. Hamilton L. Smith considers * that 

 Mr. C. M. Vorce's paper on this subject j is marked by careful, well- 

 matured statements, and that the conclusions at which he has arrived 

 are quite correct. He has not the least doubt that the diatoms are 

 enveloped by a membrane, out of which the stipes, tubes, &c, are 

 formed. "The movements, so curious and so varied, are yet con- 

 nected with the structure of the frustule, and we must not ignore this 

 in attempting to explain them, e. g. the Nitzschice, which have a con- 

 tinuous raphe, that is, without median nodule or break, move in the 

 most lively manner, they are also long and slender ; the stalked forms 

 move when free, Cocconema, for example, in a long curve, Gompho- 

 nema, straight ; the Navicula group move in straight lines, but not in 

 so lively a manner as the Nitzschice. All these, except the last named, 

 have a median nodule. The Surirellece, which have the raphe along 

 the four expansions, or alee (two for each valve), move more sluggishly, 

 rolling over frequently, and the Amphiprorece and other twisted forms 

 rock or twist as mentioned by Mr. Vorce, while the circular forms, 

 like Coscinodiscus, which have the raphe probably all round the 

 margin of the cingulum or connecting zone and edge of the valve, do 

 not move at all, or if so, very sluggishly. The movement then is 

 more or less regulated by the structure of the frustule, and in any 

 explanation we must not forget this. The careful observation of 

 facts meanwhile should not be neglected, and the publication of them 

 may give the clue or hint that will guide some other observer, 

 possibly, to the true solution of a phenomenon as marvellous as it is 

 at present inexplicable." 



* Amer. Mon. Micr. Journ., iii. (1882) p. 85. 

 f See this Journal, ante, p. 394. 



