NEW MYXOPHYCEAE FROM PORTO RICO 



27 



quite definitely in rows in the medium-sized colonies, the colonies 

 often becoming much lobed when old; tegument thin, smooth, 

 and hyaline. 



Growing in company with other ^Myxophyceae on a wall, Juan 

 Martin, Fajardo, no. 732 h, type. 



This species is certainly aberrant. It does not conform to 

 any known genus in all of the stages of its life cycle. In the 

 young stages, the colonies, up to 8 cells, resemble a typical spe- 

 cies of Chroococcus. From this time on, the development is not 

 symmetrical. Certain cells cease to divide temporarily or per- 

 manently, while others become very active, eventually resulting 

 in a colony more or less lobed and irregular in form. The divi- 

 sions proceed in three planes, the cells remain cuboidal, having 

 thin, hyaline walls and are arranged in rows. In this stage 

 the colony is not unlike certain species of Pleurocapsa. The 

 material is in all stages of development and there are no gonidia. 

 The colonies seem to break up at maturity, freeing the cells 

 which then become spherical and develop a special wall. Al- 

 though not a typical Anacystis, it seems to correspond more 

 nearly to the stage of develojiment in the life cycle of that genus 

 than to any other. 



ENDOSPORA gen. nov. 



Cells dividing in three planes, approximately perpendicular 

 to each other, resulting in cuboidal to more or less spherical 

 colonies ; cells more or less angular, with membranaceous walls ; 

 all cells in the colony at maturity loi'oducing resting spores by 

 thickening on the inside of the original separating walls, the 

 spores being liberated by the dissolution of the colonial wall. 

 Type species, Eyidospora rubra. 



The genus possesses a combination of characters not found 

 in any other genus of the Chroococcaceae. The combination 

 seems sufficient for generic distinction. I am therefore propos- 

 ing the above diagnosis under the term Endospora to take care 

 of several collections whose characters would not permit their 

 being placed elsewhere. The new genus has some features which 

 remind one of the genus Pleurocapsa, as it does likewise some 

 mem^Ders of the genus Chroococcus, but neither of these genera 

 produces, so far as is known, endogenous resting spores by the 

 secretion of a special wall around the Avhole protoplast of each 



