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parent purple. Favellee lateral or subterminal, rather large, with two to 

 three iuvolucral spines. Tetraspores common, whorled round the 

 dissepiments, scarcely immersed, very prominent, roundish, tripartite. 

 Substance rather firm, somewhat cartilaginous, and not very perfectly 

 adhering to paper. Colour, dark purple, almost black in the mass, the 

 pellucid articulations only becoming apparent when seen through a 

 magnifier. 



This beautiful sj)ecies seems by no means rare on the British shores, 

 growing on rocks, corallines, and the smaller Algte, and frequently 

 forms a dense dark, almost black curtain on the peqDcndicular sides of 

 shaded rocks, looking very much both there and on paper hke braided 

 ringlets of black hair. 



From C. diainhamim it is readily distinguished by its much more 

 slender cylindrical stems, very dark colour, short articidations, and 

 straight, not incurved apices. The same characters will also separate 

 it from C. deciirrens, together with the peculiar arrangement of the 

 coloured cellules in that species. 



Tetraspores appear to be common, and are very prominent, sur- 

 roimding the dissepiment like a string of beads loosely strung. Favellse 

 seem to be rather rare, as we have only met with them once ; spurious 

 favellse are more frequent, such as are found on G. Botryocarimm. These, 

 however, contain no true spores as in the other, and appear to be only 

 a kind of warts or suioei-fluous growth, and possibly have no other 

 relation to the fructification than in appearance. 



From the very dark colour, and the shortness of the articulations, 

 except towards the middle, the present species, when its dark colonized 

 fronds hang suspended from its native rocks, has much more the appear- 

 ance of some of the fibrillose Polysiphonice than of any of its congeners, 

 and we can still remember having gathered it the first time as Polysiphonia 

 fihrata, and it was not till viewed in the light of the microscope that 

 we became aware of our mistake. 



There are some Algee which, however plentiful among the neighbour- 

 ing rocks, are rarely seen among rejectamenta on the beach, and the 

 present species seems to be one of the number. We can well re- 

 member when the smallest fragment of Pliyllox>hora ruhens or mem- 

 hranifolia was quite a treasure to us, in our simple ignorance that in 

 the neighbouring rock-pools these and many other real rarities were 

 growing in greatest luxuriance. These plants, it may be presumed, 

 are less exposed in their sheltered rock-pool to be torn from their 

 native home by the angry surge, yet there are others less pro- 

 tected, and yet seldom find their way to the sandy beach. C. acan- 

 ihonotum grows in abundance on the most exposed rocks, and yet is 



