342 Myxophycece 



tion between their median cells, and the apical cells are about six 

 times longer than their diameter. 



A. Normanii W. & G. S. West is known from Devonshire as an epiphyte 

 on Batrachospermum moniliforme. Thickness of filaments 5'5 12'5/i, of 

 trichomes 3'5 5'5 p ; fig. 158. 



Order II. COCCOGONE^E. 



In this order the plants are unicellular or colonial, commonly 

 occurring as colonies of unicells enveloped in a copious gelatinous 

 investment. The colonies vary much in size and shape, being 

 spherical, ellipsoidal, or expanded gelatinous masses. The cells are 

 of varied form and are disposed in a variety of ways within the 

 mucous envelope. The latter is sometimes conspicuously lamellose, 

 but more often it is hyaline and structureless. 



The Coccogoneas constitute the lowest group of the Myxophyceas, 

 and indeed they are the most primitive of all the Algse. They 

 occur free-floating, or more rarely as epiphytes, and some of them 

 form gelatinous masses on wet rocks. Not a few are regular and 

 abundant constituents of the freshwater plankton. 



The normal method of multiplication is by simple cell-fission, 

 the larger colonies ultimately breaking up to form smaller ones. 

 Sometimes young colonies arise at the sides of the older ones by 

 a process of budding. Rounded asexual spores or gonidia have 

 been observed in some species, being formed within the wall of a 

 mother-cell. 



Zoogonidia are unknown. 



There are two well-marked families. 



Family 1. Chamaisiphoniacece. Cells epiphytic, with a distinct 

 base and apex ; reproduction only by the formation of gonidia. 



Family 2. Chroococcacece. Cells or colonies free-floating or form- 

 ing a gelatinous stratum, very rarely epiphytic, not differentiated into 

 base and apex ; multiplication by simple cell-division (very rarely by 

 gonidia). 



Family 1. CHAM.SISIPHONIACE^E. 



The plants of this family are epiphytes, generally occurring in 

 clusters around the filaments of larger Alga3. They are in all 

 cases differentiated so as to present a distinction between base 

 and apex, and reproduction occurs by the formation of a number 



