20 



MEMOIRS OF THE KEW YORK BOTANICAL GARDEN 



blue-green, homogeneous, 6-7.5 n diam., 10-14 n long ; resting 

 spores of the same shape as the cells, but slightly enlarged and 

 surrounded by a thin, smooth, hyaline, membranaceous wall; 

 tegument opalescent, ample (8-12 m tliick), homogeneous 

 throughout the colony ; spores sometimes germinate in the 

 mother utricle, or tegument. 



GroAving among the Myxophyceae on rocks, between Utuado 

 and Adjuntas, no. 1640 a, type. 



The majority of the species of Anacystis have either spher- 

 ical cells or cells which are more or less irregular and angular. 

 A. cylindracea departs from the rule as to the form of the cells, 

 but conforms to the tyjDical species in its life cycle. Starting 

 from a single cell the mature colony is built up by cell divisions 

 after the usual manner, the resulting cells having no visible dif- 

 ferentiated membrane, but all are embedded within a common, 

 homogeneous, more or less gelatinous matrix or tegument. At 

 maturity the cells develop a thin, firm, membranaceous, smooth, 

 hyaline wall, becoming resting spores of the typical sort. At 

 this stage it may depart from the usual procedure. The resting 

 spores germinate in position before the dissolution of the parent 

 utricle. A new gelatinous matrix, or tegument, is laid down 

 within the membranaceous wall. The cells then have the ap- 

 pearance of certain species of GloeotJiece with the usual special, 

 or individual tegument. Sooner or later these young colonies 

 are liberated and the new life cycle continues independently. 



Anacystis compacta sp. nov. 



Plate 4, figure 36 



Colonies spherical to irregular in outline, free, 25-60 p diam. ; 

 cells slightly angular, closely packed together in the juvenile 

 stage, becoming rounded, almost spherical, at maturity, 4.5- 

 5.5 M diam., bright aeruginous, homogeneous ; resting spores sub- 

 siiherieal, with a conspicuous, smooth wall, 6-6.5 n diam. ; tegu- 

 ment firm, smooth, homogeneous, close-fitting, hyaline when 

 young, becoming yellowish or brown. 



Growing on bark of a tree trunk, in Caguas, no. 439, type. 



This species may be distinguished from others by the closely 

 compacted, angular, bright blue-green cells embedded within a 

 close-fitting, firm tegument, hyaline in juvenile stage, becoming 

 yellow or brown at maturity. 



