380 THE MICROSCOPIST. 



5. Carpomitra. Receptacles terminal, at tips of the 

 branches. 



8. CHORDARIACE.E. Frond cartilaginous or gelatinous, 

 of horizontal and vertical filaments (jointed) interlaced. 

 Unilocular sporanges from the base of the vertical fila- 

 ments forming the epiderm of the frond, and multilocular 

 sporanges developed later from filaments surrounding the 

 former. 



1. Chordaria. Axis cartilaginous, dense, filaments of 

 circumference unbranched. 



2. Mesogloia. Axis gelatinous, loose, filaments of cir- 

 cumference branching. 



9. MYRIONEMACE^E. Frond tubelike, crustaceous or 

 spreading as a crust, of filamentous structure. Unilocu- 

 lar and multilocular sporanges attached to the superficial 

 filaments and concealed among them. 



1. Leathesia. Frond tuber- shaped. 



2. Ralfsia. Frond crustaceous. 



3. Elachistea. Frond parasitic, of a tubular base, bear- 

 ing pencilled erect filaments. 



4. Myrionema. Frond parasitic, forming a flat base, 

 bearing cushionlike tufts of decumbent filaments. 



10. ECTOCARPACE^I. Frond filiform, jointed. Unilocu- 

 lar sporanges, ovate sacs at ends or intermediate joints of 

 the filaments and multilocular sporanges of minute jointed 

 filaments in similar situations. Antheridia with spermato- 

 zoids in Sphacelaria. 



* Frond rigid, each articulation of numerous cells 

 (Sphacelariew). 



1. Cladostephus. Ramuli whorled. 



2. Sphacelaria. Ramuli distichous, primated. 



* * Frond flaccid, each articulation of a single cell. 



3. Ectocarpus. Frond branching, ramuli scattered. 



