brown, oval or circular bodies which are frequently radially ar- 

 ranged; pigment-spot usually present in the broad longitudinal 

 sulcus which lies almost entirely in the posterior half of the cell. 



Key to the Species 



1. Theca with posterior spines or teeth 2 



1. Theca not furnished with posterior spines or teeth 4 



2. Theca with 2 posterior spines and 2 lateral processes G. quadridens 



2. Theca with a single posterior tooth or apiculation 3 



3. Plates distinctly visible; longitudinal furrow with a flange that 

 terminates in a posterior tooth; cells S5fi in diameter G. Gymnodinium 



3. Plates scarcely visible; longitudinal furrow without 



a flange; cells 19-28^ in diameter G. armatum 



4. Epicone conical with an apiculation 5 



4. Epicone broadly or narrowly rounded, convex; not apiculate 6 



5. Cells 36-40/ti in diameter; longitudinal furrow 



broad ( 10-12At wide) G. Borgei 



5. Cells 20-25/i in diameter; longitudinal fvurrow 



narrower than above G. Penardiforme 



6. Cells 25-31/a in diameter; plates of theca conspicuous — 7 



6. Cells 13-19-(29)/u, in diameter; plates not visible G. pulvisculus 



7. Longitudinal furrow extending to the apex of the 



hypocone; 6 postcingulars, 2 antapicals G. Kulczynskii 



7. Longitudinal furrow not extending entirely to apex 



of hypocone; 5 postcingulars, 1 antapical- G. palustre 



Glenodinium armatum Levander 1900, p. 103 

 PL 90, Fig. 7 



Cells spherical in outline, unsymmetrically divided by a broad, 

 transverse furrow, the epicone longer, almost hemispherical but 

 sharply rounded at the apex; the hypocone short, broadly rounded 

 at the pole and with a short conical projection on the left side 

 ( right side as seen from the ventral surface ) ; plates scarcely visible 

 in the thin but firm theca; chromatophores radially arranged ovoid 

 plates; pigment-spot present in the longitudinal sulcus which is 

 hardly visible but which extends from the transverse furrow ahnost 

 to the posterior pole; cells 19-28/x in diameter, 16-29.7jli long. 



Tychoplankter. Wis. 



Glenodinium Borgei (Lemm.) Schiller 1935-1937, p. 112 



[Peridinium Borgei Lemmermann] 



PI. 90, Figs. 8, 9 



Cells broadly ovoid to subglobose, the epicone high and shortly 



apiculate; not dorsiventrally compressed but round in polar view; 



epitheca with 1 apical, 2 intercalary, and 6 precingular plates; the 



[ 428 ] 



