NEW MYXOPHYCEAE FROM POKTO KICO 3 

 Synechococcus intermedius sp. nov. 



I'l.ATK 1, FKIUKK :! 



Cells free, not aggregated into a stiatuiii, iianowly cylindri- 

 cal, 6-7 M diam., 12-14 m long, bright aeruginous, lioniogeneous, 

 very thin-walled. 



Growing on the bark of trees, Caguas, no. 439 h, type ; on old 

 leaves in a stream west of Humacao, nos. 581 a and 602; east of 

 Humacao, no. 640 ; on bark near Guanica, no. 1841 c. 



Dactylococcopsis arcuata sp. nov. 



Plate 1, figure 4 



Cells 45-55 p long, 1.4-1.8 |j diam., gently arcuate, free; wall 

 very thin, contents homogeneous, yellowish green. 



Growing among other Myxophyceae on the bark of a tree 

 trunk, Caguas, no. 439 e, type. 



The specimens of this species are very sparse, but seem un- 

 mistakably to be distinct, and apparently closely related to D. 

 acicularis Lemmerm., from which it differs in being shorter, nar- 

 rower, curved, and free from refringent granules. 



Chroothece Willei sp. nov. 



Plate 1, figure 5 



Cells cylindrical, straight or more or less curved, with 

 rounded ends, pale aeruginous to slightly yellowish, without 

 tegument 5.8-6.2 p diam., 18-22 p long ; tegument 8-10 p thick, 

 hyaline, homogeneous. 



Growing in small clusters among other Myxophyceae, on 

 limestone, Hato Arriba, Arecibo, no. 1410, type. 



This is a very distinct species with relatively long and nar- 

 row cells, many of which are more or less curved. Unfortu- 

 nately, the material is not abundant, as shown by its sparsity in 

 the previously mentioned collection, the only one in which it was 

 found. 



Merismopedia Willei sp. nov. 



Plate 1, figure 6 



Families composed of 256-560 cells ; membrane more or less 

 distorted, 6.5-7.5 p thick ; cells subcylindrical in surface view just 

 previous to cell division, 4.5-6 p by 7.6 p, nearly spherical in 

 resting condition. 



