DRAPARNALDIA. 119 



placing it immediately before Ectocarpus, and of course 

 assigning to it lateral external fructification. Certain 

 species hitherto associated with the genus Draparnaldia 

 Kiitzing has removed therefrom ; these are D. stellaris, 

 which may be identical with my D. condensata, and D, tenuis, 

 and constituted a new genus for them, under the name of 

 Sti/geoclonium : this genus is not even placed in the same family 

 with Draparnaldia, but in that of Ulothricece, of which Lyng- 

 hya zonata forms the type. The following are the definitions 

 of the family and genus. 



" Ulothricece. 



'^ Trichomata mucosa tenerrima, cellulse coleogonimic^e, sub- 

 stantia gonimica in fascias transversales disposita, postremo in 

 opseospermata hologonimica plerumque quadripartita trans- 



• 55 



lens. 



« Of 



Stygeoclonium Ktz. 



" Trichoma tenerrimum, ramosum, ramulis simplicibus 

 subulatis obsessum ; cellul^e gelineas tenuissimas, abbreviatae ; 

 amyledios in fasciam transversalem collapsa35 tandem in opseo- 

 spermata quaternata turgida transeuntes." 



I cannot myself think that any essential difference exists 

 between the reproduction of Draparnaldia tenuis, &c. and 

 other DraparnaldicB. I have myself occasionally observed the 

 quaternary division of the endochrome in the smaller branches 

 of, I believe, all the species of DraparnaldicB : the circumstance 

 of the occurrence of this disposition in certain species of the 

 genus more frequently than others does not seem to me 

 to call for their separation from that genus altogether ; yet 

 Kiitzing has not merely formed a new genus for them, but 

 has referred this genus to a distinct family, — a family which 

 does indeed manifest a close affinity with Draparnaldia, but 

 which Kiitzing places in his arrangement at some distance 

 therefrom. The genus Lyngbya, of which L. zonata forms the 

 type of the family JJlotliricecE, accords with Draparnaldia in 

 the extreme mucosity and flexibility of its filaments, in j^os- 

 sessing the second mode of growth of the cells, viz. that of 

 lateral developement, in the endochrome being arranged in 



I 4 



