NEW MYXOPHYCEAE FROM PORTO RICO 



29 



in size and form, spherical to ovoid, 2.5-3.8 |j diam., becoming 

 ellipsotdal before division; colonies of two or four 7.2-8.4 jj 

 diam. ; walls pinkish or brick red ; resting spores rounded, walls 

 conspicuous and smooth. 



Growing on soil by the road to Monte Montoro, INlaricao, no. 

 1071 d, type, and no. 1077 e. 



A very large majority of the colonies in the above species 

 contain only two cells. AVhen the resting spores are forming, 

 the appearance is that of the ordinary cell-division of Syneclio- 

 coccus, and were it not for the presence of a distinct cell-wall 

 and the fact that some of the colonies came to the four-celled 

 stage by divisions in two j^lanes, it might be placed in that genus. 

 It is not quite typical of the genus Endospora, which forms more 

 complex colonies by divisions in three planes, but it forms rest- 

 ing spores after the manner of that genus. 



Endospora nigra sp. nov. 



Plate 5, figure 53 



Families free among other algae, containing 2-4, more rarely 

 8 cells, the 8-celled families 11-14 \\ diam. ; cells 3.5-5 n diam. in 

 the family, contents obscured by the very dark-colored walls, 

 in part almost black ; resting spores 5-G n diam., spherical to 

 irregular. 



Growing on trees north of Sabana Grande, no. 925, type. 



Endospora olivacea sp. nov. 



Families containing as many as 64 cells, but usually few^er, 

 varying from angular to subspherical, free or more or less accu- 

 mulated into small masses ; cells angular in the colony, 4-5 \x 

 diam., dark olive-green, wall dark olive to dark drab, firm, 

 smooth and homogeneous ; resting spores spherical to irregular 

 in form, 6-7 \x diam. 



Growing among other Myxophyceae on a wall in Caguas, no. 

 462 a, type. 



Endospora olivacea is similar to E. rnhra and E. mellea, but 

 may readily be distinguished by the dark olive or drab color. 



Placoma Willei sp. nov. 



Pl.VTE 6, FIGURE 54 



Colonies 75-100 u (up to 350 jj) diam., spherical, subspherical 

 or irregular in outline, tough and cartilaginous, more or less 



