ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 277 



Arctic Diatoms.* — P. T. Cleve describes the diatoms collected by 

 M. Kjellman during the expedition of the ' Vega ' from the following 

 sources: — Arctic diatoms from the ice near Cape Wankarema and 

 near East Cape ; from the surface in Behring's Sea ; fresh-water 

 diatoms from Japan ; diatoms from algae collected on the island of 

 Labuan, near Borneo ; from algae and coarse bottom-mud collected 

 near Point de Galle, Ceylon ; and from bottom-mud between Aden 

 and Bab-el-Mandeb. The Arctic material contained a very large 

 number of species, which varied to an astonishing extent, so that in 

 many cases it was scarcely possible to trace out the limits of the 

 species. On the other hand, samples from the bottom of the North 

 Siberian Sea were quite free from diatoms. The descriptions, &c., 

 are in English, and several new species are described. 



A few new species are also described by the same authority,! 

 collected during the Arctic expedition of Sir George Nares. 



Pelagic Diatoms of the Baltic.t — A. Engler describes the pelagic 

 diatoms gathered in the Baltic, chiefly in scum on the surface of the 

 water in the bay and harbour of Kiel. Different times of the year 

 are distinguished by the appearance of different genera and species. 

 Among the more interesting forms observed was the remarkable genus 

 Chretoceros, provided with horns or bristles from 5 to 20 times the 

 length of the cylindrical part of the cell, the cell-contents being in 

 communication throughout. Of this genus many species are known 

 in the Arctic and Pacific Oceans ; six are now described from Kiel Bay, 

 one of them, G. Grunowii, new, was found with spores. 



Diatoms of Lake Bracciano.§ — M. Lanzi has examined for diatoms 

 the water from the middle of this lake, and finds that, like the pelagic 

 species, they differ from those found in shallow water. The swimming 

 deep-water species found were Fragilaria crotonensis Edw. (Nitzscliia 

 Pecten Brun.), Cyclotella comfa var. oligactis Grun., G. comensis Grun., 

 and Asterionella formosa Hass. Those found near the shore, living 

 on plants, stones, &c., belonged to the genera Navicula, Stauroneis, 

 Mastogloia, Gymbella, Amphora, Gocconeis, Achnanthes, Gomphonema, 

 Staurosira, Synedra, Epithemia, Surirella, Gymatopleura, &c. 



* Cleve, P. T., 'Diatoms collected during the expedition of the Vega,' 60 pp. 

 (4 pis.), Stockholm, 1 883. 



t Joiirn. Linn. Soc. (Bot.), xx. (1883) pp. 313-7. 



j Ber. Deutsch. Bot. Gesell.,i. (1883^,- Gen.-Versamml. in Freiburg, pp. x.-xiii. 



§ Atti Accad. Pont. Nuovi Lincei, xxxv. (1883) May 21. See Bot. Centralbl., 

 xvi, (1883) p. 257. 



