290 RHODOPHYCE.E. 



times carried from one locality to another stones bearing individuals of 

 this species, which continued to prosper in spite of the change of habita- 

 tion, I steeped many of them in lukewarm water, afterwards in boiling, 

 and no part of the Batrachosperm appeared, under the microscope, 

 to have undergone the slightest disorganization by these immersions, 

 and certain sprigs, replaced in their native place, continued to vegetate 

 after these experiments. I do not think that there exist other vegetables 

 which boiling water does not immediately disorganize, there are not 

 others that can resist temperatures so opposite." Bory. 



Plate CXXIII. Portion of filament X 200 diam. 



var. Boltoni. Cooke. 



This variety differs in the large size and very globose form 

 of the joints of the whorls. The apices are very often setiforrn. 

 SIZE. Cellules -025 x '02, or -022 x '018 mm. 



This variety, found by Mr Thomas Bolton, of Birmingham, seems to 

 differ sufficiently to be worthy of notice as a distinct variety. In colour 

 it was a beautiful green, with a tendency to pass into blue in drying. 



Plate CXXIV. Portions of a filament X 200 diam. 



var. stagnate. Ag. 



One or two inches long, blue or steel-blue. Whorls of the 

 stem confluent, of the branches distant. 



Rabh. Alg. Eur. iii., 406. 



Batrachosperma ludibunda stagnalis, Bory. Ann. Mus. xx., 

 p. 42. 



Batrachospermum stagnale, Hass. Alg. p 107. 



Conferva jontana nodosa, &c., Dill. Muse. f. 44. 



" This variety has great resemblance in form and diameter to con- 

 fusnm, ; it is nevertheless shorter, bnt as thick. Its whorls are round 

 and distinct ; they are more approximated the one to the other in the large 

 stems, about which they are sometimes even confused. Their colour is 

 a greenish-yellow, pale and livid." Hassall. 



var. alpestre. Shuttleworth. 



Frond black, very mucous, much branched, alternately form- 

 ing very obtuse angles with the principal filaments . Whorls of 

 the stem spherical, distinct, but approximate, branches com- 

 pressed. 



Bairacliospermum alpestre, Hass. Alg. Ill, t. 14, f. 2. 



" This species is easily recognized by the eye alone, either in its recent 

 or dried state ; in the former its size, great lubricity, jetty black colour, 

 and approximate, yet for the most part, exactly sphaerical whorls, are 

 remarkable ; in the latter, in which also the black tint is preserved, it 

 may be distinguished by the multiplicity of its branches, which are, 

 except the primary ones, exceedingly short and irregular, and issue from 

 the main filaments almost at right angles, and by their non-moniliform 

 appearance. In drying, also, it shrinks considerably." Hassall. 



