48 Clarence J. Elmore 



Gomphoncina fibula Breb. in Ki'itz. Spec. Alg., p. 65. i82p. 



Peronia erinacea Breb. & Arnott in Micr. Jour., p. 16. 1868. 



Sceptroneis erinacea (Breb. & Arnott) Schiitt I.e. 



PI. 2, figs. 51-53. 



Cells cuneate both in valve and girdle view with upper end 

 capitate, 40-50 /a long; terminal nodules distant from the ends; 

 striations rather broad but indistinct, 15-16 in 10 /x, every fourth 

 or fifth striation heavier than the others, interrupted by a pseudo- 

 raphe ; girdle face with marginal striations ; many of the cells vari- 

 ously distorted, as in fig. 52 ; stipitate, single or from two to four 

 cohering. 



Phalarls Lake, and in rapidly-flowing water at Long Pine, Tekamah. 

 Conata, Norris, S. Dak. 



II. Meridion 



Meridion Ag. Syst. Alg., p. XIV, 2. 1824. 



Etym. from Gr. /Ae/at^w, divide. 



Eumeridion Kittz. Bacill., p. 42. 1844. 



Oncosphenia Ehr. in Ber. Berl. Akad., p. 7^. 1845. 



Cells resembling Denticula; valves with transverse septa between 

 which are delicate granular striations, the striations but not the 

 septa interrupted by a clear space (pseudoraphe) which is very 

 delicate and often very difficult to distinguish ; general form in 

 valve view linear-lanceolate with the modification that it tapers in 

 wedge form from apex to base ; ends roimded, the larger end often 

 capitate by a neck-like constriction just below the pole; cells in 

 girdle view wedge-shaped with straight margins and truncate ends, 

 the septa and striations extending to the girdle. After division 

 the cells remain attached to each other so that the cells form fila- 

 ments which vary according to the number of cells from fan-shape 

 to circular. When a large number are formed the filament is 

 wound spirally around the central axis. In the filament the septa 

 of neighboring cells correspond with one another so that in the 

 filament the septa form unbroken concentric lines. Filaments 

 floating free. Chromatophores numerous, small. 



