ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 131 



developed etar-shaped chromatophores with distinct globular pyrenoids. 

 They bear a very close resemblance to the Mesotsenium form of Pabnogloea 

 in the condition in which the cells are found after long-continued dry 

 weather. Between these cells and the ordinary cells of the moss protonema 

 are all grades of transition. 



This retrogressive metamorphosis of the protonema occurs with several 

 species of moss, especially when growing in moist slimy situations. Under 

 favourable conditions the cells are capable of vegetative bipartition, com- 

 mencing with the pyrenoids and chromatophores. It has been pointed out 

 by Schmitz * that pyrenoids occur as low down as the Anthoceroteae, and by 

 the present author f that they are found in the Phycochromacefe when in a 

 state of retrogressive metamorphosis, but not when in the ordinary filiform 

 condition. 



The general conclusions drawn from these observations by the author 

 is that the PhycochromaceEe must no longer be regarded as the primitive 

 form of algae, their half-saprophytic mode of life and the occurrence of 

 highly organized substances imbedded in their protoplasm indicating their 

 true position as derivatives from higher forms of life by retrogressive meta- 

 morphosis. 



Acanthococcus.l — Herr P. F. Eeinsch gives a full description of this 

 genus of PalmellacesB, founded by Lagerheim on Eeinsch's Pleurococcus 

 vestitus. Fourteen species are described, twelve of them new, obtained 

 from gatherings in Germany, Scandinavia, and the United States. They 

 appear to be extremely abundant in fresh water among larger algae, and 

 are probably generally mistaken for the zygospores of desmids, though 

 often to be seen at periods of the year when these are not to be met with. 

 The structure and biology of Acanthococcus differ but little from those of 

 Palmella. The perfect cell divides into 8-16 daughter-cells, which remain 

 but a short time in connection, being set free by the deliquescence of the 

 outer membrane. After this breaking up, the gelatinous outer layers of 

 the daughter-cells undergo a variety of changes, developiog into warts, 

 spines, and other prominences characteristic of the genus and of the 

 different species ; this being their resting condition. After hibernation 

 these divide into 4-8-16 daughter-cells with smooth walls. They are best 

 distinguished from the zygospores of desmids by the nature of their cell- 

 wall, and by containing, when mature, coloured drops of oil instead of 

 vacuoles of water. 



Sphserogonium, a new genus of Phycocliromace8e.§ — Dr. J. Eosta- 

 finski describes seven species of this new genus nearly allied to CJiamsesiphon, 

 but differing from it in being unicellular. These two genera, together with 

 Clastidium and Dermocarpa, make up the family Chamsesiphonefe. 



New Hsematococcus.ll — Dr. F. Blochmann describes a new species of 

 this genus to which he gives the name Hsematococcus ButscJiln, correspond- 

 ing in the main in its history of development to Chlamydomonas. It 

 differs, in the swarming condition, from H. pluvialis in having no distinct 

 chromatophore, and in possessing numerous much-branched pseudopodia of 

 a uniform green colour. In the centre of the protoplasmic body is the 



:' » See this Journal, 1883, p. 405. t See this Journal, 1885, p. 691. 



t Ber. Deutsch. Bot. Gesell., iv. (1886) pp. 237-48 (2 pis.). Cf. this Journal, 1884, 

 p. 273. 



§ E. i. S. Akad. Krakau, x. (1883) pp. 280-305 (1 pi.). See Bot. Centralbl., xxvii. 

 (1886) p. 352. 



II Ber. Heidelberg. Med. Naturh. Ver., 1886 (22 pp. and 2 pis.). See Bot. Ztg., 

 xliv. (1886) p. 676. Cf. this Journal, 1886, p. 1006. 



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