ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 337 



Priiigsheim, arise from zoospores, and form intermediary swarm-spores 

 between zoospores and spermatozoids ; from these androspores are 

 formed later the spermatozoids. The dwarf males of the CEdogoniaceiB 

 are analagous to the dwarf germinating plants of Cha^tophoroidffi ; their 

 special sexual character is connected with the highly-developed sexual 

 differentiation of the Q^ldogoniacece. The gynandrous and makrandous- 

 dioecious forms stand on a higher plane than the nanandrous, w^hich, 

 being on a lower level of sexual differentiation, require the help of the 

 dwarf male in order to reach the same degree of sexual differentia- 

 tion. The CEdogoniaceffi show a closer connection with the chaBto- 

 phoroid than with the ulotrichoid Ulotrichales. 



Ceylon Species of Caulerpa.* — N. Svedelius publishes the first of a 

 series of papers deahng with the marine flora of Ceylon. The present 

 contribution is an ecological and systematic study of the Ceylon species 

 of Caulerpa, in which the subject is treated under the following main 

 headings. (1) Introduction. (2) On the mode of life of the Caulerpas. 

 (8) On the different kinds of variation in Caulerpas. (4) Taxonomy ; 

 definition of the species. (5) On the geographical distribution. (6) 

 List of the species described. As to the ecological conditions of the 

 various species, the author finds that in a preponderating number of 

 cases the substratum consists of firm, rocky coral ground ; but very 

 commonly, too, Caulerpa grows on soft bottom, in sand, in coarse gravel, 

 or even in soft mud carried out to sea by rivers, etc. He discusses 

 different ecological types, as distinguished by varying developments (1) 

 of the root-system, (2) of their assimilation system. After some remarks 

 on the difference between morphological and adaptational characters in 

 Caulerpa, the author describes the different kinds of variation in the 

 genus, of which he recognises six. Passing on to the taxonomy of the 

 species, he states his view that narrow, rather than broad, species-limits 

 tend to clearness ; and following out these lines, he describes twenty-one 

 species (among them two novelties) as occurring in Ceylon. Certain 

 species which had been sunk into varieties of other species are revived 

 once more, and many new forms are defined and figured. The geo- 

 graphical distribution of the genus is treated very thoroughly under the 

 headings of distribution (1) of the Caulerpas in Ceylon ; (2) of the 

 Ceylon Caulerpas in other places ; and (;->) of Caulerpas in general. 

 Under the last section, the interesting fact is pointed out that of the 

 50-60 species known, 12 are common to the tropical Atlantic and the 

 Indian-Pacific Ocean, being about half the sum total of the Ceylon 

 species. No species occur along the South American coast, and t he Cape 

 flora is very poor in this genus, so that there is no station between these 

 widely separated points, the West Indies and Ceylon, which has a similar 

 Caulerpa flora. It is difficult to account for this fact, and the author 

 suggests the possibility of a prehistoric passage between North and South 

 America, in the position of the present Isthmus of Panama. 



Algological Notes.f — M. Mobius describes a "breaking of the 

 waters " in Frankfurt-am-Main, composed of three species of Cyano- 



* Ceylou Marine Biological Reports, No. 4 (1906) pp. 81-144 (51 figs, in tex t). 

 t Hedwigia, xlvi. (1907) pp. 279-87 (6 figs, in text). 



