Io4o 
Var. montanum Schhudle. — Antioquia: n°» t and 2. 
234 . Cosmarium répandu m Nordst. forma minor W. and G. S. West (— C. odon- 
topleurum Boy and Brss.). — - Anlioquia : n° 4 - 
235 . Cosmarium retusiforme (Wille) Gutvv. forma abscissa (Scumidle) Borge. — 
Anlioquia: n os 1 and 2. Cundinamarca : n» 23 . 
236. Cosmarium retusum (Periy) Rabenh. Yar. inaequalipellicum W. and G. S. 
West. Monogr. Brit. Desm. III, 1908, p. 267 (= C. inaequalipellicum W. and G. S. 
West, i8q5). — Antioquia: n° s 1, 2, 3, 4 and 8. 
237. Cosmarium subæquale sp . now. 
C. submediocre, circiler 1 Vg-plo longius quam latum, profundissime constrictum, 
sinu angusto-lineari ad extremum subamplialo; semicellulæ triangulares, base recta, 
angulis inferioribus late rotnndatis et in parte superiori cum undulo vix conspicuo, 1 a t e- 
ribus concavis, angulo apicali late rolundato et ad apicem cum membrana incrassata ; in 
centro semicellularum tumoribus parvis tribus, lumore uno juxta isthmum et tumoribus 
binis superioribus horizonlaliter dispositis ; a latere visse ovato-pyramidalæ, angulis 
basalibus rotnndatis, lateribus cum tumore depresso et parvo infra medium, apice late 
rotundato; a vertice visæ ellipticæ, po I i s rotundatis, tumoribus parvis tribus utrobique; 
membrana punctata, punctis ad angulos semicellularum majoribus. Pyrenoidibus binis. 
Long. 64 p- ; lat. 3 g p.; lat. apic. i 4 p-; lat. istbm. i 3 p.; crass. 28 p.. (PI. XXIII, 
fig. 63 ). 
Antioquia : In ditches between Medellin and America, Central Andes; al lit. i 55 o m. 
No 6. 
This species is a close ally of C. aequale Turner (in lv. Sv. Vet. Akad. Handl. 
Bd. XXV, n» 5, r 8 g 3 , p. 64 , t. 1 1, f. 3 i), but is distinguished by ils larger sizc, ils 
proportionately longer cells, ils lliree central tumours (wliicli cause t lie side and vertical 
views to be enlirely different), and by its conspicuously punctate cell-vvall. Borge lias 
recorded C. aequale from Argenlina (cfr. Arkiv for Botanik utgifv. K. Sv. Vet. -Akad. 
Bd. VI, 1906, p. 7 c. fig.) and be describes and figures tbe semicells as having a chloro- 
plast with one central pyrenoid. In C. subaequale there are two pyrenoids in each 
semicell. 
238 . Cosmarium subarctoum (Lagerh.) Racib. ; W. and. G. S. West, Monogr. 
Brit. Desm. 111 , 1908, p. 3 r , t. 68, f. 6-8. 
Var. minutissimum yar. rîoy. 
Cellulæ minutissimæ, semicellulæ, ad isthmum plus minusve tortæ. 
Long. 6, 5 - 6 , 8 p. ; lat. 5 , 6-6 p. ; lat. istbm. 2,8 p. ; crass. 3 , 4 - 3 , 7 p. (PI. XXII, fig. 46 - 47 )- 
Antioquia : Laguna above Medellin, Central-Andes ; altit. 23 oo m. n os j and 2. 
This variety is one of tbe very smallest of known Desmids. It is about one-third 
tbe size of lyjoica 1 G . subarctoum , but is otherwise in no way different from that species, 
the cells ofwhich, as in this Columbian variety, are often sligbtly twisted at tbe islbmus. 
Among other minute species of Cosmarium should be mentioned C. suevicum Kirchner 
