4 COCCOPHYCEJ3. 



SIZE. Cells -004--007 mm. ; fam. -018 mm. (Rabh.}, cells 

 004--006 mm. (C). 



Rabh. Alg. iii. 24 ; Kirch. Alg. Schl. p. 115. 

 Protococcus valgaris, Kntz. Spec. p. 199. 

 Protococcus communis, Kutz. Tab. i., f. 3. 

 Pleurococcus communis, Desm. Exs. 1, 1203 ; ii. 603. 

 Hcematococcus vulgaris, Hass. Alg, p. 333, t. 71, f. 5. 

 Chlorococcum vulgare, Grev. Sc. Cr., Fl. No. 262. 



On the trunks of trees, moist walls, &c. Common everywhere 

 throughout the year. 



" Plant of a lively full green colour, spreading very extensively over 

 the trunks of trees, and staining the fingers on the slightest touch. Gra- 

 nules very minute, exceedingly numerous, densely aggregated, and form- 

 ing an uneven surface. They are perfectly free, semi-transparent, and 

 adhere together in an opposite manner by fours." Greville. 



Plate II. fig. 1. a, natural size ; b, cells X 400 diam. 



Fleuxococcus angulosus. (Corda) Meneg.Nost. t.4,, f. 5. 



Cells single, or 2-4, associated (04) in families, deep green, 

 nestling in greenish, rather gelatinous stratum, cell-membrane 

 thick, diaphanous. 



SIZE. Cells -007--013 mm. (Rabh.}. 



Rabh. Alg. iii. 25. Kirch. Alg. Schl. p. 115. 



Protococcus angulosus, Corda in Sturm Fl. ii. 18. 



Microcijstis angulosa, Kutz. Linna3a, viii, 374. 



Protococcus palustris, Kutz. Tab. i., t. 4. 



On the stems and leaves of aquatic plants. 



In the Kew Herbarium copy of Rabenhorst's Algae Exsicc, No. 327, 

 under this name, only Chroococcus turgidus can be found, so that it is 

 not quoted above. 



Plate II. f. 2. Cells magnified 400 diam. 



Pleurococcus (?) mucosus. Rabh. Alg. in. p. 26. 



Cells very small, of variable size, single and 4-16, associated 

 in globose families, scattered, or aggregated in a gelatinous 

 green stratum. Cell-membrane very thin, hyaline, contents 

 homogenous, decussately divided; nucleus rounded. 



SIZE. Cells 0023--0003 mm. (Rabh.}. 



Protococcus mucosus, Kutz. Tab. i., t. 4. 



Hcematococcus theriacus, Hass. Alg. p. 333, t. 78, f. 9. 



On the naked ground. 



Dr. Allmann compares its appearance to inspissated syrup. 

 Plate 22. Jig. 3. Cells magnified 400 diam. 



Pleurococcus Beigelii. Ruch 8f Rabh. 



Aerial, very small, very pale greenish, aggregated in numerous 

 globose families, encircling the hair. Cell-membrane rather 

 thick, colourless, contents very finely granular, sporangia con- 

 taining 12-20 gouidia ; nucleus globose. 



