228 FRESH-WATER ALGJE OF THE UNITED STATES. 



Judging also by an illustration in Cooke's British Algce, 

 M. laevis, Arch., is entirely distinct from our plant. The 

 conjugating connecting tube is comparatively narrow, the 

 spore small, not wider than the diameter of the filaments 

 and decidedly elliptic. 



Plate CXLVI, figs. 1, 2, two pairs of filaments conju 

 gated ; zygospores forming, and matured. 



MOUGEOTIA MlNNESOTENSIS, Wolle. 



Diameter of filaments, 15-18 /-i ; cells 4-5 times as long as 

 broad. Zygospores very large, spherical, diameter 60 yw. 

 General appearance near the preceding, but proportions of 

 cells and spores, and size of filament, all distinct. From 

 the comparatively few specimens seen, judge it a different 

 species from the preceding M. Sphaerocarpus. 

 Pond, near Minneapolis, Minnesota. 



Plate CXLVI, fig. 3, two filaments in conjugation ; spores 

 mature. 



MOUGEOTIA DIVARECATA, Wolle. 



Diameter of vegetative filaments, about 20 /* ; cells 4-10 

 times longer than broad ; zygospores average 45 yu ; cells 

 more or less diverging between the spores. 

 Ponds, Pennsylvania. 



Somewhat like the two preceding species in the spherical 

 spores, but differing in size, also in length of cells, and in 

 the recurving of the same. 



Plate CXLYI, fig. 4, two conjugating filaments with 

 matured spores. 



MOUGEOTIA DELICATULA, Wolle. 



Diameter of vegetative filaments, 12-14 yu ; cells 4-6 times 

 longer than broad ; zygospores spherical, diameter 25-30 yw. 



Shores of St. Lawrence River, Canada. 



Plate CXLVI, fig. 5, conjugated filaments with spores 

 matured. 



These four species are introduced with some degree of 

 hesitancy as new species of Mougeotia. They evidently be- 

 long to this genus, but whether absolutely distinct species 

 may riot be so certain. They were found in distinct, and 

 widely separated localities, never in large quantity, and not 

 all so frequently as to remove all doubt of constancy in the 

 specific characteristic features given. They are unlike any 

 European species known. Cooke's figures represent very 

 different forms ; possibly incorrectly, because not strictly in 



