(in Jahreshefte Verein. für vaterl. Nalurk. in Wiïrlt. 1902, p. 347 c. fig.), whicli lias a 
lenglh of G, 5-7 , 5 y. and a breadlh of 5-6 y. ; and C. hiverne var. barbaden.se G. S. West 
(in Journ. Bot. XL 1 I, 1904, p. 286, (. 464 , f. 17) wilh a length of 7, 3-7, 7 y. and a breadtli 
ol 7,4-8 y.. Wilh neither oi lhe.se liny lomis can the présent variety be confused. 
239. Cosmarium subcostatirm Nordst. forma. 
Forma semicellulis allis ut in var. Beckii sed granulis centralibus ut in forma minore. 
Long. 33 y.; lat. 28 y. ; lat. isthm. 9 g. 
Cundinamarca : no 22. 
240. Cosmarium subtile (W. and G. S. West) Lütkem. in Verhandl. der k. k. zool.- 
botan. Ges. Wien, 1910, p. 4 fi 4 - Penmm subtile W. and G. S West in Journ. Boy. 
Micr. Soc. 1897, P- 479 , (• 6, fig. 8, 9: Monogr. Brit. Desm. I, 1904, p. 92, (. 8, 
f. 27-29. 
Forma membrana cellularum crassiore. 
Long. 18 g; lat. r r ,5 y.; lat. isthm. 11 t x (PI. XXII, fig. 5 i). 
Cundinamarca: n° 24. 
24 1. Cosmarium subtilissimum Spec. nov. 
C. minimum, deücatissimum, duplo longius quam latum, levissime constrictum, sinu 
vix conspicuo ; semicellulæ semi-oblongæ, lateribus subparallelis (levissime sursum diver- 
gentibus), apice late rotundatis ; a vertice visa? circulares; membrana tenuissima et glabra; 
chromatophora singula in cellula unaquaque cnm pyrenoide singulo. 
Long, r 5 - 1 5, 5 y.; lat. 7,5-8 y; lat. isthm. 6, 2-6, 7 y. ; crass. 7,3-8 y. (PL XXII. fig- 45 ). 
Antioquia : Bog near the Laguna above Medellin, Central Andes ; altit. 23 oo m. N" 5 . 
Tliis species should be compared wilh C. perminutum nob. (= Cylindrocystis minu- 
tissima Turner), from which it differs in its more cylindrical cells, in vvhich the semicells 
are slighlly wider at the apex than the base, and in the single chloroplast (with one cen- 
tral pyrenoid) in each cell. The cell-wall is also much more délicate. 
242. Cosmarium subtriordinatum W. and G. S. West. — Antioquia : n os 1 and 2. 
243. Cosmarium subtumidum Nordst. — Antioquia : n os 5 and 6. Cundinamarca: 
n os i4 and 23 . 
244 - Cosmarium tinctum Bai. fs. — Cundinamarca: n» 24. 
245. Cosmarium trachypolum W. and G. S. West. — Antioquia: n os 1, 2, 3 and 4 - 
246. Cosmarium venustum (Bréb.) Arch. var. hypohexagonum W. West. — Anlio- 
quia : n° 5 . 
247. Xanthidium armatum (Bréb.) Babenh. — Antioquia: n° 5 (abondant). 
248. Xanthidium Mayori spec. nov. 
X. médiocre, circiter r Vs - !*^ 0 longius quam latum (sine spinis), profunde constrictum, 
sinu lineari extrorsum ampliato ; semicellulæ transverse oblongo-hexagonæ, lateribus 
inferioribus et superioribus leAÔter convexis, apice recto, angulis laleralibus et apicalibus 
spinis subulatis leviter curvalis binis instructis, etiam spinis similibus in medio marginum 
Iateralium superiorum et in medio apicis ; in centro semicellularum verrucis binis trans- 
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