136 DESMIDS OF THE UNITED STATES. 



St. pentacladum, Wolle. Plate XLIII, fig. 15; Plate XLIV, 

 figs. 15, 16. 

 Of the same general type as the preceding. It has five 

 rays, end view, but these are more slender, the body is smaller 

 and the apices are more spreading. 



Diameter 40-7* n. 



Gilder pond, Mt. Everett, Mass., and in waters scattered 



throughout New Jersey and Pennsylvania. 



St. leptcx ladum, Nord. Plate XLIV, tigs. 4, 5. 



Semicells subtrianglar, end broadly rounded, furnished with 

 small rudimentary teeth ; within the margin a small tumor ; 

 margins serrate-crenate ; base truncate, superior angles pro- 

 duced laterally, each into a long, thin, incurved, granularly 

 rough arm with a bi-tri-furcate apex ; in vertical view, fusi- 

 form with an obtuse angled inflation in the middle. 



Diameter 80 100 fi.) length about 25//. 



The original, typical plant from Brazil, is described by the 

 author, and figured by him with the arms strongly incurved, 

 and body longer than our form. The plant.- identified as of 

 thisspecie>, have the arms o< arly horizontal, and often strongly 

 recurved. 



They occur frequently in ponds of New Jersey, Massa- 

 chusetts, Minnesota, Pennsylvania, Florida and doubtless in 

 many other Stab - 



St. i. i:\ij. atorium, Nord. Plate XLIV, fig. 19. 



Seiuieells -nl >< [tiadrangular, top somewhat produced with one. 

 or two, small aculei at each angle; inferior angles rounded : 

 sides produced, each into a long, thin, colorless ray, margins 

 crenate-dentate, apex bi-tri-furcate ; vertical view oval, pro- 

 duced on opposite sides into a long thin arm. 

 Diameter L00-125 /'. 



Var. uxguj.atim, Wolle. Plate XLIV, figs. 17, 18. 



Beside having the apices of the ray- tipped with a -ingle 

 claw-like -pine, they are usually shorter and stouter, varying 

 as the figures. 



This variety is from Florida; the typical forms from Den- 

 mark Pond, Passaic Co., New .Jersey. 



