ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 267 



Algological Studies.* — Dr. A. Hansgirg has collected into a volume 

 the results of observations already published elsewhere on the following 

 points, viz. : — (1) The structure and phenomena of motion of the 

 Oscillariaceae ; (2) the polymorphism of algae ; (3) the classification of 

 some fresh-water algae ; (4) the algae of Bohemia ; (5) alga-like proto- 

 nemata of mosses. The following additional observations are made : — 



The genus Glaucothrix Krch. should be united to Plectonema among 

 Cyanophycese. 



The genus Allogonium is identified with Asterocystis Gobi and 

 Chroodactylon Hansg., and the name must take precedence of all other 

 synonyms. 



Xenococcus (Kerneri) is distinguished by marked generic characters 

 from most other ChamiBsiphonaceae and ChroococcaceaB. 



The blue-green swarm-cells described by Ehrenberg, Perty, Stein, 

 Schmitz, and Zopf, and previously regarded by the author as derived 

 from various Schizophycefe, he now treats as a separate group of 

 Phycochromacefe under the name Cryptoglsenacese. 



There is a genetic connection between the Eugleneae, which are 

 reckoned among the Flagellatae and the PhycochrornaceaB, especially the 

 Oscillariaceae. 



The Cylindrocapsa found by Hansgirg in the botanical garden at Prag 

 is apparently a variety of G. geminella Wolle. The genus belongs to 

 the oogamous Confervoideaa, but must be separated from Sphseroplea, and 

 established as the sole representative hitherto known of a new family. 



Ulvella lens is nearly related to Enteromorpha and Viva, and appears 

 to be a protonema-like structure of these Ulvaceae. 



The author is unable at present to assign their exact systematic 

 position to Protoderma viride Ktz. and Hormospora Breb. 



Sphaeroplea.f — M. N. W. P. Kauwenhoff has afresh examined the 

 structure and development of this very rare alga. The comparative 

 length and breadth of the cells he finds to vary to an extraordinary 

 degree ; sometimes the former will hardly exceed the latter, while in 

 other cases it may be as much as ninety times as great. The plant is 

 monoecious, and the number of oogonia and antheridia, as a rule, very 

 nearly the same. Sometimes alternate cells will be transformed into 

 the two different kinds of organ respectively. The author observed 

 plants consisting only of two cells, one of each kind. The fertilized 

 oospores generally hibernate within the parent-cells, the contents having 

 changed to a brick-red colour, and it is only in the spring that there 

 escape from each oospore three or four zoospores. The usual size of 

 the oospores is about 0*02 mm. ; the outer wall is strongly cuticularized 

 and verrucose. As each zoospore escapes from the oospore, forcing 

 itself through an orifice in its thick wall, it changes its form from 

 ellipsoidal to vermiform ; after its escape it again becomes pyriform or 

 fusiform, and is furnished with two cilia. This developes directly into 

 the young alga, consisting at first of a single fusiform cell with both 

 extremities elongated into a flagelliform point. 



After the unicellular filament of Sphseroplea has obtained a certain 



* Hansgirg, A., Physiol, u. Algol. Studien, 187 pp. and 4 pis., Prag, 1887. See 

 Bot. Centralbl., xxxii. (1887) p. 226. Cf. this Journal, 1884, p. 435; 1885, pp. 495, 

 684, 1037 ; 1887, pp. 125, 623. 



f Arch. Neerl. Sci. Exact, et Nat., xxii. (18S7) pp. 91-144 (2 pis.). Cf. this 

 Journal, 1883, p. 888. 



