204 SUMMAKY OF CURRENT RESEARCHES RELATING TO 



rhizoids, whereas the roots of the rock and coral Caulerpa, on the 

 contrary, are commonly directly divided into several branches, which by 

 degrees are divided into a great multitude of thin rhizoids." The form 

 of the rhizoids may vary in the same species according to the substratum 

 on which it grows. Under the heading of " The different types of 

 assimilation-shoots in Caulerpa, and their ecological adaptation to the 

 surrounding external conditions," the author criticises the published 

 views of Reinke as to their uniformity of external conditions, and 

 maintains that among Caulerpas there is sufficient variation in this 

 respect to account for much of the variety of form in the genus being 

 caused by adaptation. He divides the genus into species which have 

 (1) leaf-like, bilateral assimilation-shoots, and (2) radial species, and he 

 finds that Caulerpas must be regarded, to a great extent, as ecologisms 

 which are highly variable and adapted to particular growing places. 

 There are, of course, certain variations which are not ecological, but 

 the whole subject must be treated by means of experiments, and more 

 knowledge is required before the variability of the species can be 

 satisfactorily explained. Nine species are recorded from the Danish 

 West Indies, on each of which the author gives critical notes and adds 

 illustrations. 



Plankton of the Yang-tze-kiang.* — E. Lemmermann publishes the 

 first records of the plankton of Chinese rivers. He took six samples 

 between Chingkiang and Kiukiang, and he enumerates the species f ouud 

 therein, which included 10 Schizophycese, 8 Chlorophycege, 5 Conjugates, 

 1 Flagellate, 54 Bacillarige ; he makes remarks on some of the species 

 and describes several novelties. Finally, he states that the plankton of 

 the Yang-tze differs from that of previously examined rivers by the 

 predominance of Lysigonium varians De Toni, Synedra ulna Ehrenb., 

 S. longissima var. subcapitata Lemm., Surirella calcarata Pfitz., and 

 Diaptomus, the presence of Pediastrum clathratum Lemm. and Surirella 

 elongata Lemm., and the absence of certain typical forms. 



Phytoplankton of Ceylon.f — E. Lemmermann publishes the first 

 records of phytoplankton from Ceylon. The material was collected by 

 Borgert and Willey, partly in Gregory Lake near Nuwara Eliya, 

 and partly in Colombo Lake. From Gregory Lake are recorded 4 Schizo- 

 phyceas, 6 Chlorophyceas, 4 Conjugatae, 2 Flagellatae, 1 Peridiniale and 

 10 Bacillariales. Remarks are made on the species of Melosira and 

 Pediastrum, which occur there ; a new species, Lyngbya Borgerti, is 

 described, as well as a new variety, ceylanica, of Dinobryon cylindricum. 

 In Colombo Lake were found 6 Schizophyceae, 9 Chlorophyceae, 3 Con- 

 jugate, 1 Flagellate, 3 Bacillariales. The phytoplankton of this lake 

 is poor, and the species, with three exceptions, are not well represented. 

 All except two are found in European waters. 



Swarm-spores of Fresh-water AlgaB.J — A. Pascher publishes an 

 account of his experiments, extending over four years, on certain Chloro- 



* Archiv Hydrobiol. u. Planktonkunde, ii. (1907) pp. 534-44 (1 pi.), 

 t Zool. Jahrb. Abt. Systematik. xxv. (1907) pp. 263-8. See also Hedwigia, 

 xlvii. (1908) Beibl., p. 69. 



+ Stuttgart : Luerssen, Bibliotbeca Botanica, xiv. heft 67 (1907) 116 pp. (8 pis.). 



