MICRASTERIAS. 123 



M. CRUX-MELITENSIS, Ehrb. Plate XXXIX, fig. 3. 



Semi cells indistinctly five lobed ; lobes bifid, subdivisions 

 short, and furcate at the apices. 



Plate XLV, figs. 4, 5, two semi-cells differing somewhat 

 from the figures on Plate XXXIX, from Minnesota. 



Diameter 100-125 /*. 



Not so frequent as M.furcata, to which it often bears a 

 close resemblance ; it is similarly divided, but the incisions 

 are not so deep, the subdivisions not so elongated, rather 

 stouter and less divergent ; end lobe less exserted. 



M. DICHOTOMA, Wolle. Plate LXIII, fig. 2. 



Somewhat longer than broad, smooth or finely punctate ; 

 semi-cells three lobed ; lateral lobes twice bifid ; the ultimate 

 lobules (four resulting from one) deeply furcate or clawed at 

 the ends ; the polar or end lobe exserted on a cylindrical 

 neck with two diverging arms clawed at the ends. 



Diameter with arms 1/5-200 yu.; length the same to one- 

 fourth greater. Length of body 115 yu. ; breadth of neck 

 15-17 //. 



Hitherto found this species in three localities only : ponds, 

 Malaga, and Bamber, N. J., and Harvey Lake, Luzerne 

 County, Pa. 



M. RINGENS, Bailey. Plate XXXIX, figs. 1, 2. 



Oblong, semi-cells three lobed, with a series of granules 

 inside of most of the margins ; basal lobes divided by a deep 

 notch into two spreading arms, obtuse or slightly dentate at 

 the apices ; terminal lobe exserted, emarginate, extremities 

 obtuse. 

 Diameter 125-150 /<. 



Obtained this species from Florida only, collected by J. D. 

 Smith. 



Var. SERULATA, Wolle. Plate XLVII, fig. 15. 



In size and form the same as the original type from Florida. 

 Bailey describes it as "granular near the margins," but not 

 so serrated. This new variety has the margins distinctly ser- 

 rated, besides having the granules or mucros near the 

 margins. 



Diameter 115-130 //. ; length 125-145 p. 



Found in large numbers in White Bear Lake, Minnesota, 

 bv Miss E. Butler. 



