FLO RIDE A: 211 



packed vertical filaments. The species of Hildenbrandtia form rose- 

 coloured incrustations on rocks, stones, and shells in salt or (H. rivularis, 

 Ag.) running fresh water. The tetrasporanges are either terminal cells 

 of special filaments, enclosed in a gelatinous coating and rising verti- 

 cally from the flat thallus ; or they are formed in nematheces, in external 

 wart-like protuberances, or in depressions in the surface of the thallus. 

 The cystocarps are also either formed in nematheces, or are external, 



FIG. 188. Hildenbrandtia prototypus NarHo. Vertical section through thallus, showing 

 three conceptacles with cystocarps ( x 300). (After Kiitzing.) 



springing from moniliform fertile filaments. It is stated that there are 

 sometimes two kinds of carpogone, one provided with a trichogyne, the 

 other not. After a carpogone of the first kind has been fertilised 

 through its trichogyne, it puts out a fertilising-tube or 'ooblastema- 

 filament,' which impregnates a carpogone of the second kind. In 

 Hildenbrandtia a large number of antherids are developed from a single 

 cell of the thallus.' 



LITERATURE. 



Schmitz Sitzber. Niederrhein. Gesell., 1879. 

 Borzl Rivista Scientifica, 1880. 

 Petit Bull. Soc. Bot. France, 1880, p. 194. 

 Wollny Hedwigia, 1886, pp. I and 125. 



The HELMINTHOCLADIACE^E (including Nemalieae, Batrachospermeae, 

 and Chaetangiaceae) comprise a number of marine (Helminthocladia, Ag., 

 Nemalion, Ag., Liagora, Lmx., Galaxaura, Lmx., &c.) and fresh- water 

 (Chantransia, Fries, Batrachospermum, Roth, Thorea, Bory) forms, the 

 relationship of which to one another is uncertain, and the family is not 

 likely to be one that will be ultimately retained. The fresh-water 

 species are mostly of small size, but of great beauty from the elegant 

 symmetry and arrangement of the branches. The ' frond ' of Liagora 

 and Galaxaura is calcareously incrusted, like that of a coralline ; that of 



P 2 



