150 DESMIDS OF THE UNITED STATES. 



ST. GRALLATORIUM, Nord. Plate LV, fig. 19. 



Semi-cells subquadrangular, 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 creuate -dentate, apex bi-tri-furcate ; vertical 

 view oval, produced on opposite sides into a long thin arm. 



Diameter 100-125 p. 



Var. UNGULATUM, Wolle. Plate LV, figs. 17, 18. 



Besides having the apices of the rays tipped with a single 

 claw-like spine, 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. 



ST. FUSIFOEME, Wolle. Plate LV, figs. 20, 21. 



Semi-cells in front view, narrow fusiform, lateral angles 

 drawn out into long, colorless arms, margins crenate dentate, 

 apices bifurcate ; back or end broadly rounded or straight, 

 crenate ; end view fusiform. 



Diameter 125-138 /*. ; length 38 /*. 



This species appears to be related to the preceding two, but 

 varies from both in form of cell ; from St. leptocladum, in the 

 longer, stouter, and straighter arms, and from St. grallatorium, 

 in the absence of the produced back and the aculei. 



Denmark Pond, New Jersey. 



ST. IOTANUM, Wolle. Plate LXII, figs. 5-7. 



Very minute; semi-cells quadrangular, .angles drawn out 

 into thin, diverging, granular rays, each about as long as the 

 diameter of the body; apices obtuse; end view tri radiate. 



Diameter, including the rays, 15-20 //. 



The rays are so minute, they appear like a single series of 

 fine granules. 



Found this very small species quite numerous at Oceun 

 Beach and at Malaga, N. J. 



ST. ANKYROIDES, Wolle. Plate LXII, fig. 4 and variety fig. 3. 



About as long as wide, granularly rough; semi-cells cylin- 

 drical with enlargement towards the convex end ; sides pro- 

 duced laterally into narrow, elongate, slightly tapering, in- 

 curved arms, margins granulate-crenate, apices bifurcate ; 

 end view quadrangular, four-rayed. 

 Diameter 82 ju. ; length 75 /*. 



The only water which hitherto furnished this new species 

 is a pond near Malaga, Xew Jersey. 



