ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 667 



portions of the thalhis also show a polarity of the organism. Want of 

 light causes irregularities in growth of the thallus. Adverse influences 

 cause disintegration and formation of bud-like bodies, which develop in 

 a similar manner to the isolated portions. Germination of the zygotes 

 (as also that of the vegetative organs of multiplication) results in a 

 protonema-like growth, which precedes the beginning of the Cod i inn 

 thallus. 



New Chlorophycese from New Zealand and Tahiti.* — F. Brand 

 describes four alga? collected by Tilden which he found among a 

 number of other species sent to him. The first of these, from Tahiti, 

 represents, in the author's opinion, the type of a new genus of Udoteae, 

 Rhytisiphon tahitense, to other members of which group he compares it, 

 omitting, however, to point out the remarkable likeness it bears to 

 Chlorodesmis comosa. The other algas described are Cladophora stewart- 

 ensis from Stewart Island, Xew Zealand, Rhizoclonium Jissum from 

 fresh-water in New Zealand, and Boodlea composite f. irregularis n.f. 

 from Tahiti. The new species are figured. 



West Indian Chlorophyceae.f — F. Borgesen writes on some Chloro- 

 phyceaa from the Danish West Indies. He adds two species of Caulerpa 

 to the list previously published, of which one species, C. Vickersii, is new. 

 It represents the C. ambigua recorded from Barbados by A. Vickers 

 and, in part, the C. ambigua of Okamura. It is here fully described and 

 figured. The author then deals with the specimens of Halimeda found 

 by him, and discusses the views of Howe as to the species limits and 

 characters. He agrees with that author in keeping separate H. tuna 

 and H. discoidea Decaisne, and gives his reasons. He divides the latter 

 species into two varieties, var. typica and var. platyloba, comparing var. 

 platyloba with the corresponding deep-water variety of H. tuna, i.e. var. 

 platydisca. The two species, with their varieties, are distinguished by 

 the size and form of the utricles of the subcortical layer, and by certain 

 characters of the peripheral utricles. The author next discusses the 

 vexed question of nomenclature of H. incrassata and H. tridens, and 

 gives his reasons for accepting H. incrassata as the true name for 

 the species. He disagrees with Howe in regarding f. monilis as a 

 species, and reduces it again to a variety, as also the H. simulans of 

 Howe. On the other hand he describes and figures a form gracilis of 

 var. typica, and two new forms of var. monilis. A new variety, ojnni- 

 tioides, is described for H. gracilis, which well defines the marked West 

 Indian variety of that species. In dealing with Bryopsis, the author 

 regards the species of the B. plumosa group as being mere varieties of 

 that species, and records his finds accordingly. Vaucheriadichotoma Ag. 

 is recorded, and a new species of EnUromorplia, E. chsetomorphoides. 

 Notes are given on Blastophysa rJtizopus Rke. and Endoderma viride 

 Lagerh. 



Development of Costaria, Undaria, and Laminaria.J — K. Yendu 

 has had opportunities for years of collecting and examining the early 



* Ber. Deutsch. Bot. Gesell., xxix. (1911) pp. 138-45. 

 t Bot. Tidsskr., xxxi. (1911) pp. 127-52 (figs, in text). 

 1 Ann. of Bot., xxv. (1911) pp. 691-715. 



