438 DESCRIPTION OF \_Pnlygastriea. 



division often figgvcgated and connected in longitudinal scries by 

 the development of numerous siliceous off-shoots or radicles. 



Rhizonotia resembles JEunotia or Amphora, or indeed Cocconeis, and 

 is attached to Conferva, found in various rivers of Australia. The 

 lorica has 5 longitudinal strias, and appears rather rough or granular, 

 but is very transparent ; the contents are coloiuicss, or very pale 

 green. 



EnizoNOTiA Meh. — Striated, rough or granular, but crystalline and 

 diaphanous. By its mode of self-di\'ision, it becomes branched three 

 to ten times. Within is a greenish granular matter. In Swan E,iver, 

 Australia. 



Genus Ehizoselenta (Ehr.) — Its characters resemble those of Pyxi- 

 dicula and of GdUonella ; but the lorica is tubular, with one extre- 

 mity rounded and closed, whilst the other is attenuate and multifid, 

 as if terminating in little roots (radicles.) 



These singular beings, as to their systematic arrangement, are 

 yet doubtful; Ehrenbcrg having only met with imperfect fossil 

 examples. 



R. Americana. — Testules smooth, hyaline, tubular, interrupted 

 by septa, one end round, the other styliform, and either simple or 

 sending out branches like rootlets. Length of fragments 1 -480th; 

 breadth varies greatly. Fossil in Yirginia and Maryland. 



E. (?) larlata. — Testule short and small ; breadth exceeding the 

 depth; with the habit of Bicladia ; central portion very narrow, 

 transversely linear ; apex presenting a short thick beak (rostrum) 

 which is bearded (barbata). Length 1-1 152nd. Virginia. 



E. Pileolus. — Short and small; the width equalling the depth; 

 with the habit of Bicladia ; middle portion transversely linear ; ob- 

 long, with a smooth median umbo posteriorly ; with a short rostrum 

 in front, and branched. Diameter 1-1 320th. 



E. Campana. — Testule large, with a conical extremity, much 

 attenuated and terminating in rootlets ; surface minutely granular. 

 Length 1 -264th. Bermuda. 



E. calyptra. — Testules broad, conical, campanulate, smooth ; apex 

 attenuate, acute, recalling in figure the calyptra of the mosses. A 

 fragment. Long diameter 1 -480th. Southern Ocean. 



E. ornithoghssa. — Testules tubular, conical, smooth and slender, 



