6 



MEMOIRS OF THE XEW YORK BOTANICAL GARDEX 



aeriigiiioiis, hoinogeiieons ; families of 4 Avith tegument 6-7 n 

 diam., approximately cuboidal ; tegument homogeneous, hyaline. 



Growing in abundance among other species of M}-xophyceae 

 on a Avooden fence, at Hotel Nava, Santurce, no. 3, type, and nos. 

 2, 4a, 5, 142, and 143 a. It was also found growing on various 

 kinds of rock and Avails in the folloAving numerous localities: 

 San Juan, nos. 66 a, 92 h, 1993 a, 1999, 2004 c, 2007, 2011 and 

 2021 c; Kio Piedras, no. 177 \ Coamo Springs, nos. 254 a, 307 a, 

 313, 402 h, 409 h; Fajardo, nos. 682 a, 713, 717 a, 734 a, and 7.5^? a ; 

 Palermo, no. 755: Laguna Tortuguero, nos. 871 and 872; Sabana 

 Grande, no. 923 a; Mayagiiez, no. 982 h ; Maricao, nos. 1050, 1060 

 1061 and 1190; Arecibo, nos. 1337, 1363, 1368, 1372 h, 1457 and 

 1462 ; Guanica, nos. 1838 and 1841 a. 



This is an exceedingly diminutive, though distinct and Avell- 

 marked, species of Chroococcus. The sheath, or tegument, is 

 very thin and hyaline. Frequently only one of the cells in a 

 colony of tAvo diAides, leaving the colony triangular. 



Chroococcus subsphericus sp. nov. 



Plate 2, figure 13 



Families composed of 2-4 cells, free among other algae, 

 spherical or subspherical, not forming a stratum alone ; families 

 of 4, 16-19 u diam. Avitli the tegument ; single cells 8-10 p diam. 

 with tegument, 6-6.5 m without tegument, purplish drab or gray ; 

 tegument hyaline, homogeneous. 



GroAving among other Myxophyceae on a Avail by Hot 

 Springs, Coamo Springs, no. 402 a, type, and no. 403 a. 



The aboA^e-described species seems to be nearest related to 

 C. calda riorum Hansg. There is much less variation in the size 

 of the cells, and the color is not so intense, as has been attributed 

 to that species. 



Chroococcus mediocris sp. nov. 

 Plate 2, figure 14 



Families composed of 2-4 cells, free, not forming a definite 

 stratum alone; single cells spherical, bright aeruginous, finely 

 granular; families of 4 very angular, 9-11.,") p diam. Avithout 

 tegument, 15-18 m diam. Avith the tegument; tegument hyaline, 

 homogeneous, smooth. 



GroAving in association Avith numerous other species of algae 

 in Laguna Tortuguero, no. 831 h, type. 



