38 DE6MTD8 OF THE UNITED STATES. 



Faded specimens of the striated forms are best adapted for 

 examination ; the striae, barely discernable in green condition, Income 

 distinct ; the cases flatten somewhat in drying, the breadth in the 

 centre increases and the ends appear more attenuated, hence some 

 allowance should be made in describing them. 



( Conjugation takes place by :i process w Inch appears the same as in 

 other Gonjugatoe. Two cells drawn into close proximity, put forth 

 small tubular prominences by which they unite, the chlorophyllous 

 cytioplasm of the two cells, concentrates at their junction, in the 

 connecting tube ; this enlarges more and inure until the whole of 

 the contents of the two cell? : i r< commingled, and condensed into a 

 seed-like mass. This becomes sn th, spherical, sometimes quad- 

 rangular, and is known as the zygospore. Compare Plate \ III. 

 The coupling usual h takes place from the concave sides, but not 

 universally; have found them united from the convex sides also. 



8] i ion I . < ells more or less cylindrical, slightly bent, ends warcely, or not at 

 :ill tapering ; zygospores orbicular or -i|i< 



( '. OBTU81 m. Breb. Plate V I. fig. 1. 



Cylindrical, lightly curved, 5 10 times longer than broad, 

 ends not tapering, broadly rounded, cytioderm colorless and 



-mooth. 



Diameter 61 I ft. 



< M'tin in gelatinous masses on planks, on the Bides "I flumes, 

 Pennsylvania. 



C. juncidi m. Ralfs. Plate VI, figs. 2, :;. 



Cells long cylindrical, somewhat curved and tapering 



towards the ends; 20-30 times longer than liroad. apices 



obtusely rounded; vacuole small and indistinct. 

 Diameter 11-12 n. 



Variable in thickness and length; occur.- frequently in 



ponds from Maine to Florida. 



( MACTLENTt \i . Breb. Plate V I. fi-. ti. 



Wry long cylindrical, slightly curved and reduced in thick- 

 ness near the ends, apices rounded ; 20-40 time- Longer than the 

 diameter. Cytioderm smooth, colorless, or yellowish, usually 

 with 1-4 transverse striae. Zygospore spherical, smooth. 

 Diameter 1 2- 13 u. 



Ponds, Pennsylvania, New Jersey. Not rare. 



