304 SUMMARY OF CURREiNT RESEARCHES RELATING TO 



a parallel table of the two classes. The various groups are discussed 

 separately in detail. Botrydium is placed among the Heterokontse, as 

 representing the equivalent of the Siphonales in Chlorophyceae. 



Tetradesmus wisconsinensis.* — G. M. Smith gives an account of 

 Tetradesmus, a new four-celled co3nobic alga, found in sluggish streams 

 and lakes in Wisconsin, and cultivated from a single cell which had been 

 isolated by special laboratory precautions. He describes the cultivation, 

 morphology, and reproduction ; and claims that this is a distinct genus, 

 and not a cultural form of Scenedesmus. He says that reproduction 

 takes place by the formation of non-motile spores by successive nuclear and 

 cell divisions. These spores then become arranged in the form of the 

 adult colony, while still inside the old cell wall. The young colonies are 

 liberated by the rupture of the mother-cell wall. The pyrenoids in the 

 daughter-cells arise de novo, and not by the division of a pre-existing 

 pyrenoid. 



Microspores of Coscinodiscus.t — H. Selk records finding many 

 examples of a Diatom belonging to the Ooftcinodiscus hiconicus series 

 containing microspores. The Diatoms occurred in plankton from the 

 Elbe, opposite the month of the Nord-Osten-Kanal. He found also, 

 young unformed specimens, which he thinks may be in part the escaped 

 microspores. 



Eunotia major. | — C. van Wisselingh describes the process of nuclear 

 division in Eunotia major Rab. He finds that it divides karyokinetically 

 or mitotically, like other Diatoms. In E. majar there appears the 

 central spindle which is characteristic of nuclear division in Diatoms. 

 Well-developed chromosomes do not occur. The nuclear structure forms 

 small short bodies of uncertain form, which draw together round the 

 central spindle, and form the ring-shaped nuclear plate ; this divides 

 into halves also ring-shaped, which separate along the central spindle 

 and develop into daughter-nuclei. As regards the chromosomes, the 

 author's results agree with those of Klebahn and Karsten, but not with 

 those of Lauterborn. 



Algological Notes. §—N. Wille continues his series of notes. 

 XXII. Studies in Agardh's herbarium. The author here describes his 

 interesting and important examination of certain of Agardh's types, 

 which need greater definition in diagnosis. These are : — 1. The genus 

 Gloiodictyon, which name he finds must fall, giving place to either 

 Falmodictyon or Trypothallus. 2. Haemato coccus Noltii Ag. = Euglena 

 sanyuinea Ehrb. 3. Protococcus viridis Ag. is fully discussed, newly 

 diagnosed, and figured. 4. Protococcus monas is discussed at length, 

 and sho\\ n to be the young autospores of Clilorella elhpsoidea Gern. 5. 

 Protococcus glomeratus represents a number of roundish algal cells, 

 belonging to no one genus, and must therefore be wholly dropped. 6. 

 Protococcus Scdicis Ag. (as recognized by Agardh himself) consists of 



* Bull. Torrey Eot. Club, il. (1913) pp. 75-87 (1 pL). 

 t Ber. Deutsch. Bot. Gesell., xxx. (1913) p. 669. 

 : Flora, V. (1913) pp. 265-74 (1 pL). 

 § Nyt. Mag. Naturv., li. Heft 1 (1913) 26 pp. (1 pL). 



