46 SYNOPSIS OF BllITISIT SEAWEEDS. 



Tins curious parasite, quite an interesting object under 

 the microscope, is found wherever Himanthalia ton a \ 8* <<- 

 thongs) abounds. It frequently completely covers the Long, 

 strap-shaped receptacle of thai plant for the space of several 



inches, forming swellings of a dark colour and very slippery 

 surface. 



64. pulvinata {The cushioned Elachista) ; tufts very minute, 



globo>e : filaments fusiform, much attenuated toward both 

 end-, the basal joints 3-4 times, the middle once and a half, 

 the apical about as long, as broad; spores linear-obovate, 

 subsosilc at the base of the filaments, Harv. Phyc. Brit. 

 Sija. p. 7. (Atlas, PL XYI. Fig. 66.) 

 Hal. South of England. At Elberry Cove, Torbay. Parasitical 

 on the fruiting branches of Cystoseira ericoides. Annual. 

 Summer and autumn. 

 In a delightful excursion, made in the autumn of 1844, 

 in company with my valued friend Mrs. Griffiths, to visit 

 the habitat of Gigartifta Teedii at Elberry Cove, we ob- 

 served that most of the fronds of Cystoseira ericoides, 

 which grows in great luxuriance on an exposed rock in 

 the cove, were infested with this minute parasite. The size 

 and shape of the filaments readily distinguish it from any 

 of the British JElachistce ; but in these characters it agrees 

 with E. rivularice, Suhr., from which it is chiefly distin- 

 guished by the globose form of the tuft. 



65. velutina ( The velvety Elachista) ; spreading in thin, inde- 



finite, velvety patches ; filaments very minute, equal in 

 diameter throughout, dissepiments slightly contracted ; joints 

 once to one and a half times as long as broad ; spores ellip- 

 tical, pedicellate, affixed to the lower part of the filaments, 

 Fries, Flor. Scan. 317. (Atlas, PI. XYI. Fig. 67.) 

 Myrionema velutinum, Endl. Sphacelaria ? velutina, Grev. 

 Hab. Atlantic coasts of Britain. Parasitical on HimanthaHa 

 lorea, frequent. 

 Elachista velutina occurs commonly on the long strap- 

 shaped receptacles of Himanthalia lorea ; but I have 

 not seen it on Fucus serratus. Mr. Balfs, who finds it 

 abundantly on the Himanthalia, remarks that it very fre- 

 quently accompanies E. scutulata, and often so closely re- 

 sembles that species that it becomes difficult to distinguish, 

 them, except by the form of the spores. Usually, how- 

 ever, E. scutulata is readily known by occurring in raised, 

 oval, shield-like patches. 



