Mr. J. Ralfs on the Nostochinere. 333 



cylindrical, truncate. Sphcero:;yga elastica, Agardh, Icones Alga- 

 rum Eurojjaearum. Cylindrospermum elonyatum, Kiitzing, Spe- 

 cies Algarum, p. 294 (1849) ; Tabulae Phycologicse, t. 99. fig. ill. 



Cromlyn Bog near Swansea, J. R. 

 Sweden, Agardh ; Germany, Braun. 



Stratum deep bluish green, tender. Filaments elongated, 

 constricted at the dissepiments. Ordinary cells about equal in 

 length and breadth ; but when dividing they lengthen, and though 

 quadrate in the recent plant they acquire shghtly rounded angles 

 when dry. Vesicular cells at first barrel- shaped, finally elliptic. 

 Sporangia cylindrical, four to eight times longer than broad, 

 their ends at first truncate, but rounded after separation. 



The moniliform filaments and shorter joints distinguish this 

 species from Sph(jerozyga leptosperma, and its elliptic vesicular 

 cells from S. Jacobi and S. Caj^michaelii. 



Plate VIII. fig. 9. a, immature filament ; h, matm-e state. 



** Filaments moniliform ; sporangia turgid^ much broader than the 

 ordinary cells. 



4. S. Broomeii (Thwaites). Filaments moniliform, elongated ; ordi- 

 nary joints suborbicular ; vesicular cells barrel-shaped or elliptic j 

 sporangia elliptic, catenate. SphcErozyga Broomeiiy Thwaites. 

 Brackish ditch at Shirehampton, near Bristol, Mr. Broome. 



Stratum bluish or yellowish green. Filaments elongated, ob- 

 tuse ; ordinary cells at first nearly quadrate, but finally orbicular. 

 Vesicular cells smooth, at first barrel-shaped, then elliptic, 

 broader than the ordinary joints, but not so broad as the spo- 

 rangia, which are elliptic and numerous. 



The gelatinous matrix is firmer than in many species of this 

 genus, and under the lens can be detected without difficulty. 



The numerous sporangia in each series distinguish Sphcerozyga 

 Broomeii from every other species I am acquainted with. 



Plate VIII. fig. 10. a, immature filament; b, mature state. 



.0. S. Berkeley ana (Thwaites). Ordinary joints spherical or slightly 

 compressed ; vesicular cells spheroidal, compressed, as broad as the 

 large turgid-elliptic sporangia. Sphcerozyga Berkeley ana^ Thwaites. 

 Brackish ditch at Shirehampton, near Bristol, Mr. Thwaites. 



Filaments elongated ; ordinary joints nearly globular, some- 

 times compressed and slightly broader than long, terminal ones 

 longer and somewhat tapering. The vesicular cells are globular 

 in dried specimens (but Mr. Thwaites informs me that in the re- 

 cent state they are compressed) ; they are nearly as broad as the 

 sporangia, which are large, broadly elliptic, and sometimes almost 

 globular. 



