Naviculncea.'] infusorial animalcules. 1-11 



SxEPiiANOGONiA quadrangula. — Testules thin, smooth, one valve 

 with foui" angles, spines and rays, and a truncated apex ; the other 

 with six rays. Diameter 1-1 152nd. Bermuda. 



S. polygona. — One valve with sixteen (?) rays and spines ; the other 

 unknown. Bailey has figured this species. 



Genus STEPnANOSinA. (Ehr.)— Loricautricular,truncate; each utricle 

 capable of spontaneous fission through the centre, which being in- 

 complete, devclopes chains ; no apertures or internal septa in the 

 disc ; lateral aspect of disc (end view of segment), with very minutely 

 dotted rays, not cellular, but with a marginal circlet (crown) of 

 apiculi (and a central smaller crown). 



In form this genus resembles Stephanodiscus, but differs from it, 

 and becomes allied to Gallionella, by its imperfect spontaneous division 

 and consequent concatenation. In GalUoneUa, however, the circlet 

 of spines is wanting. 



S. Europcea. — External surface of testides smooth, with their 

 margin finely apiculated ; chain formed of 3 to 4 segments, each seg- 

 ment (testule) 1 -2304th to 1-1 152nd in depth; rarely l-1200th in 

 width ; often wider than long, like those of Gallionella. On Tree- 

 mosses. Berlin. 



S. epidendron. — Each testule cylindrical ; the short surface, or that 

 of its depth, with very minute dotted transverse lines ; each valve 

 with a median transverse suture, which, when self-division is pro- 

 ceeding, becomes a fissure ; terminal disc with very minutely dotted 

 striae, and with both a central and marginal circlet of apiculi, the 

 central of about four. Larger diameter l-432nd; smaller l-4320tlL 

 Guiana, South America. 



S. Hamadnjas. — Testules cylindrical ; external or short surface 

 smooth, but striated along the lines of junction, and hence the 

 margin of detached joints appear denticulated ; disc radiated around 

 its margin, but the central area smooth, with some scattered dots, and 

 its middle bearing the peculiar spikelets (apiculi). Diameter l-720th. 

 This and the preceding species have their segments filled with green 

 granular matter (ovules, Ehrenberg). 



Genus STTLOBiBLiuii. (Ehr.) — Lorica cylindrical, multivalve, not 

 concatenated ; valves in a simple straight scries, like the contiguous 

 leaves of a book, with a large median aperture opening into the 



G G 



