I A.LOCYLINDRU6. >.-> 



Pennsylvania, New Jersey, ami other States. 



Fig. 16 represents a small form collected several succeed- 

 ing summers, in gelatinous masses on the muddy bottom of a 

 small pool; thousands were present; the other ( fig. 15) is the 

 larger, typical form. 



C. connatur, (Breb). Kirch. (Cosmariwm oonnatum, Breb). 



Plate XI. figs. 8, 9. 



( Jells short and thick, subcylindrical, about one and one-half 

 to two times longer than broad, ends broadly rounded; con- 

 striction forms a wide, shallow sinus; cytioderm distinctly 

 punctate. 



Diameter l"> 75 u. 



Pennsylvania, New Jersey, Florida, N> Y'>rk, Vermont, 

 Minnesota, etc.; probably distributed everywhere. 



This is j of the largest Bpecies of the genua and most 



common. The end view is nearly a perfect circle; front 

 vicu of a semi-cell constitutes about two-thirds of a circle ; a 

 distinct border is always present, and often appears Btriated. 



Var. minor, Nord. Plate XII, fig. 10. Plate XL1X. fig. is. 



This form is in all essential point- like the last, except in 

 dimensions. 



I have found almost every possible variety of size. 

 measuring in diameter from 20 to 1" ,". This fact furnishes 

 a presumptive evidence that the smaller fornix are merely un- 

 developed conditions ; young plant- evolved from sporangiums, 

 in accordance with Holmeister'- theory; Bee [UTRODUO- 

 TION p. 1!. 



C. P8EUDOOONNATU8, Nord. Plate XII, fig. 11. Plate XLIX, 

 figs. 10, 11. 

 Similar to the two preceding in form and structure, but in 

 size usually -mailer than the typical plant. The distinctive 

 feature is in the arrangement of the chlorophyl : this is not 

 homogenous, but divided in each semi-cell, in front view, into 

 two parts, and in end view, into four part-. 



Marsh pools, Pennsylvania. 



The value of the arrangement of the chlorophyl as a spe- 

 cific character, needs, I think, further corroborative evidence. 



