128 SYNOPSIS OF BBITISH SEAWEEDS. 



divaricate, irregular, obtu 

 (Atlas, PL WAX. Fig. 22 



divaricata, A<i. Bi. Hudsoni, Harv. Ulva rub 



ZTaZ>. On stones, and the smaller Algae, near low-water mark, and 

 a1 a greater depth. Annual. Summer and autumn. 

 It is still a question whether this planl really beloi 

 the genus Dudresnaia, and not rather to 2V If 



we judge it by outward habit it v\ ill be placed in the fon 

 but there is certainly an approximation in structure to the 

 latter, although the axis is less dense and somewhat dif- 

 ferently constructed. The fructification is imperfectly 

 known. I have sought in vain among a large number of 

 specimens, from different localities, for tetraspores. All 

 the specimens we have independently examined produce 

 favellidia. 



LXXIX. CEOUAXIA. 



222. attenuata (Tlw attenuated Crouania)-, frond gelatinous, 

 filiform, consisting of a jointed single-tubed filament, whose 

 joints are clothed with dense whorls of minute, multifid ra- 

 melli ; fructification of two kinds, on distinct individual-; 

 1, "favellidia subsolitary near the apex of the ramuli, af- 

 fixed to the base of the whorled ramelli, and covered by 

 them, containing, within a hyaline membranaceous peri- 

 spore, a subglobose mass of minute spores ;" 2, obovate tetra- 

 spores, of large size, affixed to the bases of the ramelli, 

 /. Ag. Ah/. Medit. p. 83. (Atlas, PL L. Fig. 229.) 

 Mesogloia attenuata, Ag. M. moniliformis, Griff. GrifFithsia 

 nodulosa, Ag. Callithamnion nodulosum, Ktz. Batra- 

 chospermum attenuatum, Bonnem. 

 II ah. Parasitical on the smaller Alga?. Annual. Summer. 



This beautiful little plant was first noticed by Eonne- 

 maison, on the northern shores of France, where it appears 

 to be of as rare occurrence as it is in England. Subse- 

 quently, Agardh detected it in both the Adriatic and Me- 

 diterranean Seas, from various localities of whose shores I 

 have received specimens, rather more luxuriant than our 

 British plants, but not affording any essential distinctions. 

 Mrs. Griffiths suggested it might prove the type of a new 

 genus, allied on the one hand to Ihidresnaiai on the other 

 to Batrachospermum, and the younger Agardh has accord- 

 : rh assig] ed to it the name it here bears. It must be 

 confessed however that, except for the very decided ■„ 

 tine, and some difference in the conceptacular fruit 



