361 



Cellulae primitivae diametio sempei mnltoties longiorcs , postca 

 dhisione repetita diametro aequales vel breviores (rarius paulo longiores), 

 omies fere fertiles. Cytioderma aut tenue (Ulothrix, Horraidium) aut 

 orassim , saepe crassissimum ei pleruinque manifesto lamcllosum (Hor- 

 misria. C\ tioplasnui initio effusum , parictalc , granula amylacca in- 

 rlmlens, postea divisione aut simplici aut repetita in gonidia trans- 

 mutatum. 



Gonidn duplicis generis : Macrogonidia (vulgo zoosporae) sphae- 

 rica, ovoidea vel ovato-oblouga , in polo postico rotundata, in polo antico 

 acutata, ciliis vibratoriis binis vel quaternis munita , saepe jam intra 

 cellulam matriialem gcrminantia sine foecundatione sexuali: Micro- 

 gonidia multo minora , forma simili , per generationcs transitorias 

 multiplicata , in polo antico ciliis vibratoriis binis instructa. Utraque 

 zoogonidia in eellulis rilorum variorum oriuntur , aut per ostium pori- 

 formc ccllulae matricalis membranae examinant aut cellulae matricalis 

 membrana dissoluta vel fatiscente in libertatem emittuntur (in Hormi- 

 dio, Schizogonio). 



De germinationc ct evolutione conf. Thuret. A. Braun 1. c. , Are- 

 schoug obs. phycol. in Act. Reg. Soc. Scient. Ups. Ser. III. Vol. VI. (1866.). 



X.CVIII. Horilliscia (Fr. 1835) Aresch. (emend. 1866): 

 Fila articulata ccllula basali deorsum attenuata subcallosa affixa, simplicia 

 noununquam passim ramulos emittentia. Cellulae abbreviatae , cytio- 

 dermate crasso, saepe manifesto lamelloso instructae, cytioplasmatc 

 viridi, parietali, granula amylacea includente praeditac. 



Propagatio fit tum macro- tum micro-gonidiis. 



Conf. fig. nostr. 100. 



Genus ab Ulothriche non nisi cytiodcrmate crassiore ct loco natali 

 divcrsum. 



(Hormotrichum Ktz.) 



a. Species aquae dulcis. 



H. moniliformis (Ulothrix moniliformis Ktz. Spec. Alg. p. 347. 

 N. 15. Tabul. phycol. II. T. 88. U. lacustris Hilsc in Kabcnh. Alg. 

 ft. 1540!). H. pallide viridis, plus minusve crispata, saepe inter varias 

 algas immixta ; articulis diametro ( x :i m — ' L6o'" = 0,000449—0,00055") 

 acqualibus vcl paulo brevioribus; cytiodermate crasso, achroo, sublamel- 

 loso (inprimis per acidum sulfuricum), ad genicula magis minusve 

 constricto. v. v. 



b. Forma paulo tenuior (Ulothrix Braunii Ktz. 1. c). 



