46 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



shaped, terminal zoogonidiangia. The spores are ordinary 

 cells from the recumbent branches which become detached. 



Leptosira Borzi. Very much like Gongrosira. The 

 thallus is in the form of a minute bright green cushion. The 

 cells are light yellow-green, the terminal cells being elliptical 

 or irregular. The zoogonidiangia are intercalated and not 

 terminal. The zoogonidia either germinate directly, or con- 

 jugate in pairs and form resting spores. The ends without 

 cilia fuse first in conjugation. 



FAMILY II. CH.'ETOPHORACE^E. 



The thallus is branched, and the branches are attenuated 

 sometimes into long hyaline hairs ; it is usually differentiated 

 into creeping and erect portions. The creeping portion is at- 

 tached by rhizoids, is branched, and is more or less torulose. 

 The cells of the creeping portion are more or less swollen, and 

 the branching is irregular. Each cell, except those of the 

 terminal hairs, is provided with a parietal irregular chloroplast, 

 containing a single pyrenoid. 



Zoogonidia, from I to 16, may be produced in each cell of 

 the thallus except those of the rhizoids and the terminal hairs. 

 They possess a red pigment spot and 2 or 4 cilia, and vary 

 much in size. Spores of a red-brown color are produced in all 

 the genera of the Chaetophoraceae. The gametes possess only 

 two cilia, conjugate in pairs, and produce zygospores which 

 rest for a short period before germinating. 



Key to Genera. 



1. Plants less than 1 mm. high, without setae 



Microthamnion* 

 Plants larger, branches attenuated, and with seta?. . . 2 



2. Filaments fine, showing little difference in character 



of stem and branch, not in tufts in gelatinous 

 masses Myxonema* 



Filaments fine, in tufts in a dense gelatinous substance 



Chcctophora* 



Filaments and main branches large, bearing tufts of 

 small branchlets Draparnaldia* 



