INTRODUCTION TO CRYPTOGAMIC BOTANY. 



155 



collections, which requires especial notice, as it is the only instance 

 I know, in this group, of the peculiar structure which it exhibits. 

 The threads at first are like those of an ordinary Tyndaridea, 

 but after a time little swellings occur on their sides in which a 

 distinct endochrome is formed, extending backwards into the 

 parent endochrome, separated from it by a well-defined mem- 

 brane, and producing either by repeated puUulation a com- 

 pound mass like that of Calothrix, or simply giving rise to a 

 forked thread. In the latter case there is no external swelling, 

 but a lateral endochrome is formed, which, as it grows, makes 



Fig. 40. • 



Threads of Cladozygia Thomsoni, Berk, in various stages of growth, 

 magnified. 



its way through an aperture whose sides are regularly inflected. 

 I have given to this curious production the name of Clado- 

 zygia Thomsoni. 



10. BuLBOCH^TEiE, Berk. 



Threads articulate, branched, fertile branchlets, bulb-shaped, 



* An appearance is figured in Cladophora fracta, by Kutzing, Phy- 

 cologia, tab. 11, fig. 5, which is of the same nature ; and something ap- 

 proaching it in CEdogonium capiUare, 1. u. tab. 12, fig. 2, i., where the 

 lateral branch sends a root down into the parent endochrome. 



