io 35 
Excepl for size (lie specimens were cpiite typical. 
ip 4 . Euastrum Turneri W. West, forma. 
Long-, 37-38 u. ; lat. 26-27 p, ; lat. apic. 18-20 p, ; lat. islhm. 6,6-7 {’■ (PI- XXII, fig. 3 g). 
Antioquia : n° 5 . 
196. Micrasferias rotata (Grev.) Ralfs. — Cundinamarca : n° 24. 
196. Micrasferias truncata Bréb. var. pusilla var. nov. 
Var. subduplo minor quam forma typica ; cellolis in ambitu subcircularibus ; sinu 
extrorsum leviter aperto. 
Long. 58 - 6 1 p. ; lat. 58 - 6 1 p. ; lat. lob. polar. 4 °- 4 ^ p-; lat. istlim. rr-i2p. (PI. XXII, 
fig. 4 a -4 3 ). 
Antioquia : Bog near t lie Laguna above Medellin, Central Andes; altit. 23 oo m. 
N° 5 (abundant). 
This variety is much less (ban lhe average size of M. truncata , and (lie outline of 
the cell is more rounded than in most forms of tliis species. M. truncata var. minor 
Wolle (Desm. L. S. 1884, t. 38 , f. 9) dillers in many ways from the Columbian variety, 
in ils general external form, in (lie shape of its polar lobe, and in (lie lobulation of lhe 
latéral lobes. 
r 97 . Micrasferias Sol (Ehrenb.) Kütz. var. ornata Nordst. 
Forma eleganlior ; long. 172 p.; lat. 168 p. ; lat. max. lob. polar. 24 p- ; lat. istlim. i 5 p. 
(Pl. XXII, fig. 44 ). 
Cundinamarca: n° 23 . 
198. Micrasferias americana (Ehrenb.) Ralfs, — Cundinamarca: n° 24. 
Long, r 2 8- 1 36 p. ; lat. roo-109 p.; lat. istlim. 21-23 p.. 
199 Cosmarium adelochondrum (Elfv.) Lütkem. (= Penium adelochondrum Elfv.). 
— Antioquia: n os 1, 2 and 5 . 
200. Cosmarium adoxum W. and G. S. West in Journ. Roy. Micr. Soc. 1897, 
p. 478, t. 7, f. 24. 
Var. denticulatum war. nov. 
Var. sinu angusto-lineari ad extremum non ampliato ; angulis basalibus rolundo- 
truncatis semicellularum cum denticulis minutissimis i -3 irrégularité!' ordinatis, angulis 
apicalibus cum denticulis minutissimis 1-2. 
Long, il p. ; lat. 10 p.; lat. istlim. 2,6 p. ; crass. 8 p. (Pl. XXII, fig. 5 o). 
Antioquia : Laguna above Medellin, Central Andes; altit. 23 oo m. N os 1 and 2. 
Also Laguna above Estrella near Medellin, ait. 2600 m. N° 3 . 
This tiny Cosmarium dillers from typical C. adoxum in its linear sinus and in the 
presence of the exceedingly minute and very délicate denticulations. The central papilla 
of the semicells is also a little smaller. In general outline it is very similar lo C. geome- 
tricum var. adoxoides G. S. West (in Ann. S. African Mus. IX, 1912, p. 86 , t. 2, f. 47), 
and it is highiy probable that C. odoxum var. denticulatum and C. geometricum var. 
adoxoides are intermediate forms belween C. adoxum and C. geometricum. 
