ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 1003 



restates liis previous view that the so-called genera Schizogonium, Hor- 

 midium, and Prasiola, are but stages in the development of the same 

 organism, there being an unbroken chain of intermediate forms between 

 them. The species of Hormidium are to be distinguished from those of 

 Hormiscia or Ulothix proper by the form of their chromatophores. 

 Those of Schizogonium and Prasiola resemble those of Hormidium. 



Structure of TJlotlirix.* — Herr G. Istvanffi describes several points 

 in the structure and details of TJlotlirix zonata. The rhizoids, for which 

 he prefers the term haptera, he finds, after a time, lose their contents, 

 and then serve the purpose simply of mechanical cells. They exhibit 

 peculiar phenomena of prolification, and almost invariably branch 

 dichotomously. 



Some of the cells are subject to a peculiar hypertrophy, swelling up 

 to fifteen or even twenty-five times the length of the ordinary vegetative 

 cells ; they are endowed with life, and are frequently divided up into 

 smaller cells ; they contain a number of nuclei. 



The cells of TJlotlirix always contain a nucleus which is visible with- 

 out special treatment. The chlorophores are stretched and ruptured by 

 the rapid growth of the vegetative cells ; they can, within a short period, 

 assume various forms and display a variety of movements. 



Bulbotrichia. — M. E. de Wildeman j proposes the suppression of the 

 genus Bulbotrichia Ktz., which he regards not as an independent genus 

 of algfe, but as being of a lichenoid nature, consisting of gonidia allied 

 to Protococcus, which are beginning to be invaded by filaments of a 

 parasitic fungus, in fact, as a lichen in process of construction. In this 

 opinion Dr. J. B. de Toni | agrees. 



Hansgirgia, a new genus of aerial Alg8e.§— Dr. J. B. de Toni 



describes an epiphytic alga found on the leaves of Antlmrium Scherzianum 

 in the botanic garden at Padua, which he establishes as the type of a 

 new genus Hansgirgia (^flahelligera), belonging to the Trentepohliaceee, 

 but distinguished from the other known genera of the family by the 

 green colour being masked by the presence of chlororufin or hfematu- 

 chrome in the cells. The vegetative structure consists of a mass of 

 chroolepidiform branched and anastomosing filaments ; these are in 

 parts distinct, forming a network, in parts more or less united laterally 

 into imperfect discs having the form of a fan. The chlorophores are 

 parietal, concealed by the orange-yellow pigment, which occurs in the 

 form of globules, and is turned violet or nearly black by zinc chior- 

 iodide. The reticulate filaments produce ovoid zoosporanges containing 

 biciliated zoospores ; their germination has not been observed, nor any 

 conjugation between them. He proposes from it the establishment of a 

 ■ sub-family, Hansgirgiese, connecting the two other sub-families of Trente- 

 pohliace^e, viz. Chroolepidege and Mycoidese. 



Chlorogonium. \\—Chlorogonium euchlorum Ehrb., placed by Ehren- 

 berg and Stein among the Flagellate Infusoria, has been carefully 

 examined by M. P. A. Dangeard, who considers it to belong to the 

 Volvociaeee, and to come very near to Chlamydumonas. It has both a 



* MT. Med.-Naturw. Classe Siebenblirg. Mus.-Vereius, xiii. (1888) pp. 53-66 

 (1 pi.). See Bot. Centralbl., xxxv. (1888) p. 122. 



t CE. Soc. E. Bot. Belg., 1888, pp. 157-9. j Loc. cit., p. 157. 



§ Ibid., pp. 151-7, and Notarisia, iii. (1888) pp. 581-4. 

 II Bull. Soc. Linn. Nurmaodie, i. 1SS6-7 (1888) pp. 160-4. 



