234 PALMELLACE^l. 



formed from the ordinary cells. Name, from crTre^wa, a seed, 

 and ffeipa, a chain. 



1. S. lilorea, Kiitz. ; filaments robust, nearly straight, com- 

 posed of very short, closely packed, compressed cells ; 

 spores elliptical, not wider than the cells ; connecting-cells 

 also elliptical, shorter than their width and not wider than 

 the ordinary cells. Harv. Phyc. Brit. t. cxiii. C. 



In muddy brackish ditches. Bavmoutb, Rev. T. Salway. Dolgelly, 

 Mr. Ralfs. Shirehampton, Mr. Thwaites. " Scarcely gelatinous, forming 

 a deep green, fleecy covering to floating plants, on which it occurs. Fila- 

 ments of considerable diameter, nearly straight. Ordinary cells of a beau- 

 tifully blue-green colour, very short and compressed, giving the filaments 

 the appearance of an Oscillatoria ; connecting-cells of a pale reddish : 

 sometimes the plant is of an uniform, dull green." Thw. Spores elliptical, 

 placed with their longer diameter at right angles with the filament, at 

 length acquiring a deep brown colour. 



2. S. Harveyana, Thw. ; " filaments much curved, com- 

 posed of cells nearly as long as broad ; spores exactly sphe- 

 rical, almost twice the diameter of the cells ; connecting- 

 cells subquadrate, rather longer than wide, and of the same 

 width as the ordinary cells." Thw. Harv. Phyc. Brit, t 

 clxxiii. C. 



Muddy ditches at Shirehampton, Mr. Thwaites. " This beautiful spe- 

 cies differs from S. litorea, in its spores being not at all compressed, and its 

 ordinary cells much longer, compared with their width. The membranous 

 sheath investing the filament is with difficulty seen, and the plant bears 

 considerable resemblance to some species of Spheerozyga. The curved fila- 

 ments and spherical spores render it not very unlike Monormia intricata, 

 from which it is, however, perfectly distinct.'' Thw. 



ORDER XIX. PALMELLACE^E. 



Sub-order HORMOSPORE^E. 

 Hormosporeae, Thw. in Harv. Phyc. Brit. t. ccxiii. 



DIAGNOSIS. Cells contained in confervoid, simple or 

 branched, tubular filaments. 



(This supposed sub-order consists of a single genus, of 

 which two species only are known, both of which have been 

 found in England). 



