ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 185 



Chloropliycese collected on the same expedition. One new genus and 

 nine new species of known genera are described. These groups also 

 reach their highest development in the summer months. The influence 

 of the fresh water, especially that of the Po, is very marked. The 

 vertical distribution attains its maximum in May in 20 metres depth 

 with about 29,000 cells ; in August, in 50 metres with about 62,000 

 cells. Light, and perhaps also salinity, are probably the controlling 

 factors. Finally, the author states that the rich supply of Flagellate- 

 and Chlorophyceae-plankton in the Adriatic plays an important part in 

 the production of organic substances by the assimilation of C0 2 . 



Metachromatic Bodies in Algae.* — Madame Moreau writes on the 

 metachromatic bodies of algae. She has examined Diatoms, Conferveae, 

 Ulothrix, Vaucheriea?, Desmids, and Conjugatas, and states that the 

 " Karyoiden " of Palla in Desinidieae and Conjugatae are identical with 

 these metachromatic bodies. She holds the same views as Guilliermond 

 and Foex that they are reserve material, and finds that relations exist 

 between them and the organs which produce reserve material in algae. 



Diatom Structure^ — T. A. O'Donohoe writes on the structure of 

 Coscinodiscus asteromphalus, and of Pleurosigma angulatum and P. 

 balticum. He discusses the views of T. F. Smith, with which he dis- 

 agrees. As regards the most correct image of G. asteromphalus in 

 photography, whether " black dot " or " white dot," he is of opinion 

 that the black dot is the more correct. The chief difference in the 

 minute structure of Pleurosigma balticum and P. angulatum. is that in 

 the former the fibrils run parallel with the raphe ; in the latter they 

 seem to run obliquely. 



Two Plankton-diatoms. $ — K. Rouppert records Chsetoceros Zach- 

 ariasi in an old bed of the Weichsel in Slonsk, and is able to complete 

 the diagnosis by measurements. He shows that Honigmann was in 

 error with regard to the " chromatophores," which are in reality resting 

 spores with a clearly silicified thick membrane. The author considers 

 that Honigniann's five species belong to one very variable species. He 

 discusses its occurrence in salt inland waters, and distinguishes between a 

 " hyphalmyro-plankton " of the brackish waters of the sea-coast and 

 another of the salt inland waters. The connexion of the former with 

 pelagic forms is clear, while the occurrence of C. Zachariasi aud 

 Atthega Zachariasi in the latter is more difficult to explain. The author 

 shows that A. Zachariasi is identical with Anthoceras magdeburgense. 

 He agrees with A. Forti in uniting Chsetoceros, Peragallia, Athega, and 

 Rhizosolenia in one group. 



Bohemian Diatoms.§ — K. Hoffmann writes on the diatoms of the 

 Kieselgur and of the waste water of the Kaiserquelle in the Soos, in 



* Bull. Soc. Bot. de France, lx. (1913) pp. 123-6. 

 t Joum. Quekett Micr. Club, xii. (1913) pp. 155-60 (1 pi.). 

 X Bull. Intern Acad. Sci. Cracovie (June 1913) pp. 298-306 (3 pis.). 

 § 8 Jahresb. Staatsrealsch. im 8 Wiener Gemeindebez. Wien, 1913, pp. 3-17 

 (1 pi.). See also Bot. Centralbl., cxxiii. (1913) p. 617. 



