T. H. BUFFHAM ON ANTHERIDIA. 299 



two together; the chromatophores appear to be smaller; the 

 contents of the cells do not shrink so much. In any case the 

 condition is an interesting one. I may add that in some 

 specimens in which tretraspores predominated there were a 

 few procarps. (A small specimen with procarps, trichogynes, 

 cystocarps and antheridia, Llandudno, July, 1886, collected by 

 a non-algological friend. The others by myself at Swanage, 

 Aug. 1890.) 



Halarachnion ligulatum Kiitz. (Ralymenia ligulata Ag.) — I 

 long searched unsuccessfully for the antheridia in this species 

 until I found a plant (Swanage, Aug. 1890) which had many 

 very thin ramuli, from '7 mm. to a fine point (Fig. 37), and, 

 especially, on the middle portions of these I detected, amongst 

 the ordinary superficial cells, a few differing from these by 

 having a few dots above a spot in the centre lower down. 

 They occur singly, or in couples, rarely many more, each single 

 antheridium being about 15 {l in diam. (Fig. 38.) They are 

 very difficult to detect, especially when fresh. Much patience 

 is required to secure a section through them. However, this 

 exhibits a cell which produces four male cells above, and these 

 emit the pollinoids which are minute. The gelatinous covering 

 rises but slightly above the general surface (Fig. 39). 



In Poly ides rotundu^ Grev. the arrangement differs from that 

 of all other algae. On the stout filaments of the plant a 

 yelloivish long patch near the apex can be seen by the naked 

 eye, projecting, but only some '2 mm. A transverse section of 

 the filament is a vertical section of the antheridial patch, and 

 shows the latter to consist of closely set, erect, colourless 

 filaments of 6 to 10 elongated cells which reach a height of 

 150-200 ^. Out of the filaments, especially the upper portions, 

 bud out numerous male cells, the whole forming a kind of 

 spike. Each cell, with a thick but perfectly hyaline wall, 

 contains a pollinoid, which is readily distinguished as it is 

 slightly granulated, spherical, and of large size, about 6 /x in 

 diam. The antheridia of this species are described by Thuret, 

 and figured in Etudes PhycoL, p. 76, PI. 37. (Margate, Aug. 

 1891, by Mr. Neeve. Cumbrae, same month, by Mr. Batters.) 



Choreonema Thureti Schmitz was demonstrated by Bornet 

 (who named it Melohesia Thureti) to be a parasite of various 

 Corallinaceous algae (Etudes PhycoL, p. 97). Harvey had sup- 



