102 SUMMARY or CURRENT RESEARCHES RELATING TO 



phyton is endowed with an amoeba-like motion, and the vacuoles 

 pulsate. They are at this time still naked; but they soon round 

 themselves off, come to complete rest, and appear to clothe themselves 

 with a delicate cell-wall. They multiply by repeated bipartition, so 

 that the cells of the host become sometimes comjiletely filled by them. 

 They then assume a somewhat angular form, and may be regarded as 

 cysts or resting-spores. In them the whole contents of the cells 

 appears to have a brownish-yellow colour, with the exception of some 

 colourless portions, which may be oil-drops or nuclei. 



In addition to these, there was found in the large cells of some 

 dying Sphagnum leaves, a second form of resting-spore, larger in size, 

 perfectly spherical, with a much firmer and often double membrane, 

 and only half-filled with the yellow pigment. Similar structures are 

 also sometimes found outside the leaves of the host. Some of them 

 also present a double appearance, the result either of coalescence in 

 growth or possibly of conjugation. The author has succeeded in 

 developing the motile form of GhromopTiyton from these resting cysts. 



With regard to the systematic position of Chromophyton, nothing 

 can yet be said with certainty. Many of the points described appear 

 to indicate an alliance with the Palmellacese. It also presents great 

 similarity to an organism described by Cienkowski under the name 

 Chromulina nehulosa, as belonging to the Flagellata Infusoria. 



Norwegian Desmids.* — The first part of a paper by N. Wille, 

 on the fresh-water Algse of Norway, is devoted to the Chlorophyllo- 

 phycete of Smaalehneu, a boggy and mossy district lying east of 

 Christiania Fjord, with a substratum of granite or gneiss. He de- 

 scribes in all 224 species of Desmidieae, belonging to 18 genera. 

 Among them are 5 new species of Cosmarium, 1 of Arthrodesmus, 2 of 

 Staurastrum, and 3 of Closterium, besides 1 of TJlothrix (Hormospora). 

 He also enumerates in the same district 13 species of Tetrasporese, 

 13 of Pediastrese, 3 of Characeae, 2 of Protococcaceae, 6 of Volvocinese, 

 4 of Zygnemeae, 3 of Mesocarpeae, 1 of Ulvaceee, 5 of Confervaceae, 

 3 of Ulotrichacefe, 1 of Chroolepidae, 8 of Chaetophoraceae, 3 of 

 Vaucherieae, 23 of QEdogoniaceas, and 4 of Coleochaeteae. 



Movements of Diatoms.j — M. C. Mereschkowsky considers that, 

 although this subject has been specially attractive, no one has hitherto 

 succeeded in furnishing a positive explanation of the phenomenon. 

 The nature of the forces brought into play, and the utter want of 

 direct positive facts which could be taken as the basis for an explana- 

 tion, resulted in hypotheses supported only by indirect proofs, and 

 for that reason as unsound as they were short-lived. 



Two hypotheses are extant. The first, which has had for its 

 advocates Max Schultze,J Pfitzer,§ and, recently, Engelmann,]] sup- 



* Forhandl. Vidensk. Christiania, 1880, pp. 1-72. See Bot. Ztg., xxxviii. 

 (1880) p. 745. 



t Bot. Ztg., xxxviii. (1880) pp. 529-40 (3 figs.). 



X "Die Bewegimgen der Diatomeen," Arch. f. Mikr. Anat., i. (1865) p. 385. 



§ ' Untersuchungen uber Bau und Entwickehing der Bacillariaceen,' 1872, 

 p. 177. 



II " Ueber die Bewegungen der Oscillarien und Diatomeen," Bot. Ztg., xxxvii. 

 (1870) No. 4. 



