ZOOLOGY AND BOTANY, MICEOSCOPYj ETC. 289 



Algae. 



Cell-nucleus in Algae.* — Schmitz supplements his previous obser- 

 vations on the presence of one or more nuclei in the cells of Thallo- 

 phytes t by the following, relating chiefly to the Floridese. 



In Batrachospermum, Chantransia, Liagora, Dudresnaya, GoralUna, 

 Jania, Melobesia, Hapalidium, Cruoria, Cruoriopsis, Peyssonelia, Petro- 

 celis, &c., he found invariably only small cells with one nucleus each. 

 The Corallinefe often manifest a coalescence of two cells of the tissue 

 by resorption of the partition-wall. In Jania rubens the mass of the 

 protoplasm has coalesced, the nuclei remaining distinct. In Spondy- 

 lothamnion multifidum,, Geramium ruhrum, gracillimum, fastigiatum, 

 strictum, and other species of the genus, besides the small cells, the 

 large cells of the stem have also only one nucleus. 



In most other species of Floridese the larger cells are multi- 

 nucleated ; for example, Spyridia filamentosa. In a large number 

 of species the smaller cells have only one, the larger several nuclei. 



Many species of Griffithsia and Bornetia, Monospora pedicellata, 

 Spermothamnion flabellatum, &c., have also several small nuclei in the 

 younger cells. The species of Gallithamnion exhibit a great diver- 

 sity ; in some species the youngest cells are uninucleated, in others, 

 like the older ones, multinucleated. 



The reproductive cells show great uniformity in contrast to the 

 vegetative cells. The tetrasporangia are always uninucleated, and 

 this is also the case with the spermatia (antherozoids) and the carpo- 

 genous cells of the procarpium. The nuclei of the sexual are always 

 larger than those of the vegetative cells. 



The multiplication of the nucleus in the multinucleated cells is 

 always effected by bipartitiou, and is independent of the division of the 

 cell itself. 



Of the remaining marine algse, the Bangiaceae, Dictyotacese, and 

 PhaBosporese have always uninucleated cells. Among Ulotrichaceae, 

 the marine species TJrospora mirabilis is multinucleated. 



The presence of several nuclei was observed in some fresh-water 

 algse, as Hydrodictyon iitriculatum and Botrydium granulatum. In the 

 Protococcacese and allied forms only a single nucleus could be 

 detected in each cell. 



Formation of Endogenous Shoots in Algse.l — In confirmation of 

 the statement of Falkenberg § of the occurrence of an endogenous 

 formation of normal branches in Bhytiphloea, Vidalia, and Amansia, 

 H. Ambronn has reobserved the phenomenon in the two last-named 

 genera, to which he adds also Polyzonia. 



Vidalia spiralis, Amansia multifida, and Polyzonia elegans and 

 incisa exhibit precisely the same phenomena as the species described 



* SB. niederrheiu. Ges. Natur. u. Heilkimcle, Bonn, 1880. See Bot. Centralbl., 

 i. (1880) p. 1281. 



t See this Journal, ii. (1879) p. 60G; iii. (1880) pp. Ill, 303, 482, 493; 

 i. (1881) p. 69. 



X SB. Bot. Ver. Brandenburg, 1880, pp. 74-6. 



§ See this Journal, iii. (1880) p. 138. 



