NEW MYXOPHYCEAE FKOM PORTO lUCO 



15 



dantly existing as single cells, those of 4 cells 7-8 m diam. ; cells 

 cylindrical, U.8-1.2 m diam., 2-3 n long, pale aeruginous; tegu- 

 nient very nearly colorless, homogeneous, about equal in diam. 

 to the cells. 



Growing on limestone, between Hatillo and Arecibo, no. 

 1377 a, type, and no. 1378 a; on a water pipe near a stream, 

 Maricao, no. 1147 a; on limestone at Hato Arriba, Arecibo, no. 

 1407 h; and between Arecibo and IJtuado, no. 1481 a. 



This is a very diminutive species of Gloeothece, when young 

 appearing with but very little tegument, and that almost trans- 

 parent. It finally develops a visible sheath or tegument, which 

 combines 2-4 cells, very rarely more, into small families, where 

 it has the typical Gloeothece character and resembles, to a less 

 degree, certain Bacteria. 



Anacystis gigas (W. & G. S. West) comb. nov. 

 Gloeocapsa gigas AV. and G. S. West.^ 



Growing in company with other species of Myxophyceae on 

 limestone, between Arecibo and Utuado, no. 1476 ; between 

 Hatillo and Arecibo, no. 1387 b ; on old wood at Hato Arriba, 

 Arecibo, no. 1397 5 ; on a wall in Fort San Cristobal, San Juan, 

 nos. 1991 c, 1993, 2002, 2003 d, 2008, 2014 c and 2021. 



A large percentage of the species of Myxophyceae collected 

 by Dr. Wille on Porto Rico are unicellular. Many of these spe- 

 cies belong and may readily be associated with more or less 

 well-recognized and clearly defined genera. Others seem de- 

 cidedly to be allied with less clearly delimited genera and before 

 these can be satisfactorily placed the limits of such genera must 

 be either more clearly defined and amplified or new genera must 

 be erected for their reception. In this instance I shall attempt 

 the former procedure. Three of such genera are Chroococcus 

 Naegeli, Gloeocapsa Kuetzing, and Anacystis Meneghini. 



Naegeli proposed the genus Chroococcus in 1849,- selecting 

 as the type of the genus C. rufescens {Pleurococcus rufescens 

 Breb.) at the same time recognizing nine other previously de- 

 scribed species, which had been placed with one or the other of 



1 On some fresh water algae from the West Indies. Jour. Linn. Soc. Bot. 30 : 

 276. pi. 16. 1895. 



2 Gattungen einzelliger Algen, 44. 



