MICRASTERIAS. 113 



M. Nokdstp:dtiam:m, "Wolle. Plate LI I, figs. 3-5. 



Cells of equal length and breadth, smooth ; semicells three 

 lobed ; the* lateral lobes divided into two subcylindrical seg- 

 ments with a wide notch between ; ends obtuse, furnished with 

 three or four small spines. Polar lobe exserted on a long 

 neck having a short conical prominence about the middle of 

 each side; the ends diverge in two pair composed of one 

 longer and one shorter, nearly horizontal, arms ; the two are 

 nearly parallel. 



Diameter 1 5( ) ft. 



Longwood pond, Passaic County, N. J., and Harvey Lake, 

 Lycoming County, Pa. 



This species has a number of distinct features; the four 

 arms of the end lobe; the protuberances of the neck; the 

 lateral lobes have something in common with M. ringens, but 

 they are smooth or finely punctate, not granulate; there is 

 something also to remind one of M. pseudofurcata, but the 

 arms are not furcate at the end-. 



Section IV. Cells circular ; semicella obscurely five lobed, the end lobe the 

 broadest. 



M. decemdentata, Naeg. Plate XXXIII, figs. 5, 6. 



Suborbicular, granulate-punctate; semicells distinctly three 

 lobed, or obscurely five lobed ; lateral lobes divided by a small 

 obtuse angled sinus into two lobelets, having straight, truncate 



margin.-, angles -lightly produced and mucronate; polar lobe 

 broadly truncate, separated from the adjoining lobe by a narrow 

 linear sinus; apex broadly convex, sometimes sinuate, lateral 

 angles slightly produced and mucronate. 



Diameter 83-100 u. 



Frequent in Florida ; have not found it farther north. It 

 differs from all forms described under this name, particularly 

 in size. The author, Naegeli, gives the diameter 40 ft. 

 Delponte quotes subalpiue forms at 50 ft.; and Lundell, the 

 Sweden plant also at 50 ft. which is only half the size of our 

 plant, but omitting the measure, the description proves them 

 identical. 



M. crenata, (Breb.) Ralfs. Plate XXXIII, figs. 7, 8. 



Cell orbicular; semicells with five shallow lobes; end lobe 

 8 





