48 ERYTHEA. 



and sent out the latter, received from Ravenel — both under the 

 name of Sirosiphon compadus. Mr. Wolle has devoted considerable 

 attention to the Sirosiphoniacese in his various writings, but it 

 certainly seems that his ideas of specific limitations were very 

 uncertain, so much so in fact that it will be very diflficult to 

 arrange his references under any satisfactory citation of synonymy. 



Stigonema ocellntum (Dillw.) Thuret is another case in point. 

 This species was sent out by Wolle labeled Sirosiphon Crameri. 

 Bornet and Flahault place Sir. Crameri Brugg. among the " species 

 inquirendae." 



Scytonema mirabile (Ag.) Bornet, found in New England by 

 Farlow (B. & F., Rev. Nost Het., Ill, 103), at Niagara Falls by 

 Wolle (Setchell, Erythea, 4, 193), and by the writer, at Manitou, 

 Colorado (1. c, 4, 89), is distributed from Iowa in Tilden, Ameri- 

 can Algae, No. 290, under the name of Scyt. Myochrous. 



Scytonema densum (A. Br.) Bornet, found by Wolle at Niagara 

 Fulls (Setchell, Erythea, 4, 191), has been found near Twin 

 Oaks, San Diego County, California, by F. W. Koch. Dr. Bornet, 

 who determined the specimen, says that it has all the characteristics 

 of Scyt. densum except the gelatinous sheath, but that even the 

 sheath in some places has the characteristics of the type. 



Scytonema caldarium sp. nov. The algae inhabiting the hot 

 springs and tiieir vicinity are always of especial interest as to their 

 likeness or unlikeness to forms found either in similar places else- 

 where or to those found entirely apart from thermal activity of any 

 kind. The specimens which are taken as the type of the species to 

 be described below, were collected at the Waterman Hot Springs 

 near San Bernardino, California, by Samuel B. Parish, April 9, 

 1897. Mr. Parish has collected the same thing in the same 

 localities many times previously, and through his kindness, the 

 writer also has had the opportunity of collecting it at the same 

 place. The alga forms more or less extended tufts on the cooler 

 portions of the rocks from which the hot water drips and the 

 temperature of the tufts approximates to 27° C. The filaments of 

 Soyt. caldnrium are decumbent or even horizontal at the base, more 



