tum sinu amplo non profundo; semicellulae semicireulares, 
eirc. ?'; circuli efficientes, ad basin saepe paullo angustatae, 
angulis inferioribus obtuso rotundatis, margine (8-) 10-undu- 
lato-crenatae erenis 2—3-granulatis, ad basin eireiter 15jugis 
granulatis (granulis in 4 series horizontales plus minus 
distinetas ordinatis), area supra granula basalia parva nuda, 
marginem versus granulatae granulis binis (intimis singulis) 
radiatim et concentrice dispositis; a latere visae rectangu- 
lares apice late rotundatae ad basim utrinque paullo tumidae, 
transverse granulatae; a vertice conspectae late ovali-ellip- 
ticae granulis transverse ordinatis, massa chlorophyllacea 
e nucleo amylaceo centrali undique radiante. Long. 38 —42u; 
lat. 26—28 u; crass. 24—26 u; lat. isthm. 18—20 u. 
257. Cosmarium pseudarctoum Nordst. noy, spec. 
C. diametro eirc. quarta parte longius, medio levissime ex- 
eavatum, a latere conspectum ellipticum, semicellulae a fronte 
visae latissime ovatae, apice truncato, angulis (superioribus) 
late rotundatis; a vertice visae circulari-ellipticae massa 
chlorophyllacea e nucleo amylaceo centrali radiante, eruciatim 
disposita. Long. 17,5—21 u, lat. 14—16 u; erass. 11514, 5u; 
lat. isthmi 13,5—15 u. 
265. Penium phymatosporum Nordst. f. majus 
nov. var. Long. cell. 25—72 u, lat. 24—26 u. 
271. Mesotaenium Endlicherianum Naeg. BB. 
grande Nordst. Nuclei amylacei 2 (vel rarissime ante 
divisionem 4) in quaque semicellula. Plasma violaceum. 
Diametr. 10—14 u; long. 29—64 u. rs: 
286. Oseillaria major Vauch. form. tenuior; 
diametr. fili 16—28 u. Be: 
295. Aphanothece saxicola Naeg. 9. aquatica 
Wittr, nov. var. Var. aquatica, thallo luteo-fuscescente, tegu- 
mentis cellularum vix visibilibus, arctis; erassitudine cellu-r 
larım 1,5—1,6 u, longit. cell. 2—4 plo majore, en 
296. Polyceystis (Clatbrocystis) aerugınosa 
Kütz. forma major diametro cellularum 5,5—6,5 u. a 
297. Polycystis prasina Wittr. nov. spec. P. thallo 
submucoso, granuloso, prasino (colore thalli siecati vix 
mutato), familiis confertis minus distinete limitatis; cellulis 
globosis, corpore phycochromaceo vacuolis magnis plus minus 
ovalibus saepe radıantibus praedito (structura haec adspec- 
tum fere elathratum eontenti cellularum effieit); diametro 
cellularum 31, —4' u. Differt a specie affıni be: viridi > 
A. Br., magnitudine cellularum minore, colore (etiam thali 
siccati) prasino, familiis minus distineto limitatis. 
298. Polyeystis Flos-aquae Wittr. nov. spec. P. 
thallo mucoso difformi, sublutescente-aeruginoso (colore thalli 
