CHOBDJJU \< : 48 



common Actinia. Prom the preceding species, /.. 2 

 leyi differs in being .-it all times of a dense and Bolid Bub- 

 stance (not, as L. tuberiformis, al first flocculent within, 

 and then hollow ), in its different colour, and more dej 

 form. 



\\1\. EtALFSIA. 



58, verrucosa (Thevoarty Ralfsia) ; frond coriaceo-crusl i 



fixed 1>\ it- inferior Burface, orbicular, concentrically toned; 



composed of densely packed, vertical, Bimple filaments; 



fructification, depressed warts, scattered over the upper 



surface, containing oboyate spores fixed to the b 



(deal filaments, Aresch. (A i las, PL \ \ 

 Hob. ( Sommon on the rocky Bhoree of the Bri1 ish Islands, between 



high- water mark and half-tide level. Perennial. Winter. 

 This singular production 'more nearly resembles, to the 

 naked eye, a crustaceous Lichen than an Alga, but its 

 structure and fructification prove it to be widely different 

 from any Lichen. There is a curiously close resemblance, 

 both in the habit, the structure of the frond, and the out- 

 ward character of its fruit, between Ralfsia and Peysson- 

 nelia; yet, according to the received notions of arrange- 

 ment, these plants must be referred to opposite parts of 

 the system. They are. however, closely analogical forms 

 in the families to which they respectively belong. Except 

 for the colour and the different formation of the spores, 

 there would be little to distinguish them. 



XXX. ELACHISTA. 



59. fucicola [The lftunu~inhabiting Elachista) ; tufts pencilled : 



filaments elongate, flaccid, membranaceous, attenuated up- 

 wards ; articulations once or twice a^ long as broad : tuber- 

 cular mass Bpherical, Fries, Fl. Scan. p. :U7. | A i las, PL X \ . 

 Fig. 61.) 

 Mjnonema mcicolum, Endl. Phycophua mcorum and Ph. 

 Lgardhii, Ktz. Conferva fucicola, VeUey. C. ferruginea, Ag. 

 Hob. Atlantic Bho a ol N >rtb Britain. Parasitical on Fucus 

 serratus and /•'. vesiculosus. Annual. Summer and autumn. 

 Common. 

 This the largest Bpecies, the Longest known, and the com- 

 monest of the genus Elachista. It infests F 

 losus and Ji 1 . serratus almost wherever these plants grow, 

 and may he f>und nearly at every season. At its first ap- 

 pearance it forms a minute pencil o( greenish tilamenU 



