CHROOCOCCACEJ]:. 213 



sion proceeds, orifices are formed in different parts, until the whole 

 becomes a coarsely latticed sac or clumsy net of irregularly lobed form. 

 Then this becomes broken up into irregular fragments of all shapes and 

 sizes (giving the stratum, a granular appearance to the naked eye), each 

 of which recommences the expanding growth, and becomes a latticed 

 frond. The internal cells are very minute, but have a distinct margin 

 with internal granules. They multiply by dividing into two and four. 

 The gelatinous frond always presents a transparent border or peripheral 

 stratum, destitute of green cells ; but no boundary membrane exists, the 

 surface exhibiting a softened or half-dissolved aspect. On the approach of 

 winter the fronds ceased to increase, and by degrees most of the gelati- 

 nous masses faded to a light brownish tint, swelled up and settled to the 

 bottom of the water in light flocculent clouds. They appear to become 

 half-dissolved, and to allow the green cells to become free, as many of the 

 latter were found free, adhering to the sides of the vessel. Perhaps these 

 reproduce the fronds in the next season. No zoospores were ever de- 

 tected." Henfrey. 



Clathrocystisroseo-persicina,, Colin., is already included in this work, as 

 Pleurococcus roseo-ptrsici/tus, pi. 2, fig. 0. 



Plate LXXXVL fig. 7. a, Thalli magnified 200 cliam. ; 6, cells mag- 

 nified 400 diam. 



GENUS 86. CffiLOSPHJERIUM. Nag. (1849.) 



Thalliis globose, small, vesicular, hollow, composed of small 

 cells, which are associated in families at the periphery, im- 

 mersed in a mucous stratum, formed from the speedily confluent 

 teguments. Increase by division of the cells in all directions, 



Ccelosphaerium Kutzingianuxn. Nag. Elm. Alg. p. 54, t. 1 c. 



Families sphasrical. Cells stibglobose, geminate, or quater- 

 nate, loosely disposed ; cell-contents blue-green, delicately 

 granulose. 



SIZE. Cells '002-'005 mm. ; families '06 mm. and more. 



Rabh. Alg. Eur. ii., 55. Quart. Journ. Micr. Sci. 1869, p. 

 197. Kirch. Alg. Schles. 254. 



In ponds, meres, &c. 



Plate LXXXVII.fig. 1. Families magnified 400 diarn. 



GENUS 87. GOMPHOSPHffiRIA. Kutz. (1836.) 



Cells wedge-shaped, peripherical, 2-4-8 associated in radiating 

 families nestling in jelly, covered with a tegument, and forming 

 a solid globose free-swimming thallus. Cells dividing alter- 

 nately in three directions. 



Gomphosphaeria aponina. Kutz. Tab. I., t. 31, f. 3. 



Thallus microscopical, blue-green, often becoming pale, tegu- 

 ment colourless, rather thick and somewhat lamellose, central 

 cells smaller, cell-contents verdigris or pale blue-green, 



