OSCILLATORIACEiE. 105 



distinct. To judge by the characters assigned by bim, many appear very closely allied 

 to each other. 



1. CaLOTHRIX confervlcola, Ag. ; filaments short, glaucous, opake, filiform, blunt, 

 rigid, straight or slightly curved, minutely tufted. Ag. Syst. p. 70. Harv. Phyc. 

 Brit. t. 254. W^jatt, Alg. Damn. No. 229. Leibleinia confervicola, Encll. M. Supp. 

 p. 221. Leibleinia chalybea, Kiltz. Sp. Alg. p. 277. (and probably other species of 

 Leibleinia of the same author). Conferva confervicola, Dillw. Conf. t. 8. E. Bot. t. 2576. 



Hab. On the filiform marine Algaj. Rhode Island shores, Professor Bailey^ 

 Mr. Olney, Mr. Hunt. (v. v.) 



Filaments about the tenth of an inch long, either forming little starry tufts along the 

 branches of the Alga it infects, or, by the confluence of several such tufts, covering the 

 branch with a continuous pile of dark ^ruginous-green threads. When seen under the 

 microscope the filaments are simple, curved, filiform, but little attenuated upwards, and 

 either separate from each other or variously combined by lateral cohesion into fascicles. 

 Their cell-wall is rather thick, and the endochrome within is of a di;U bluish-green, here 

 and there interrupted and broken into separate masses, and sometimes nodoso-incrassate 

 at short intervals. The transverse striaj are more or less distinctly seen according to 

 the age of the specimen examined. The colour varies in different specimens, from dull 

 to bright green ; and is sometimes olivaceous, and even yellowish or pale. 



This species is a common parasite on the filiform Algte, and found in many distant seas. 



2. Calothrix scopnlorwn, Ag. ; spreading in velvetty didl-green strata of indefinite 

 extent ; filaments flexuous, subulate, subattenuate, simple. Ag. Sp. Alg. p. 70. Harv. 

 Phyc. Brit. t. 58, B. Schizosiphon scopulorum, Kutz. Sp. Alg. p. 329 (and probably 

 others.) Conferva scopulorum, Dilliv. Conf. p. 39, Sup. t. A. E. Bot. t. 2171- 



Hab. Rocks near high water mark. Shores of Rhode Island, Professor Bailey and 

 Mr. Olney. (v. v.) 



This occurs in slimy and somewhat velvetty patches of indefinite extent, covering the 

 surface of marine rocks. The filaments rise from a slimy debris or matrix, which is 

 gradually accumulated. They are erect, flexuous, often very much bent, attenuated to 

 the apices, and sometimes, but not invariably, acuminate ; and they stand in the stratum 

 parallel to each other, crowded together, but not cohering in lamina;. The endochrome 

 is commonly of a dark, olivaceous green, and the cell-wall thin and membranous. Strice 

 evident. 



Generally dispersed throughout the temperate zones, both north and south. Its 

 slimy patches are very treacherous to the feet of unwary trespassers who may happen 

 to tread on them. 



