MICRASTERIAS. l0<> 



M. radiosa, (Ag.) Ralfs. Plate XXXI, figs. 1, 2, 3. 



Cell orbicular, smooth; semicells rather indistinctly five 



lobed ; lobes dichotomously divided ; ultimate subdivisions, 

 inflated, attenuated, furcate at the ends. End lobe narrow 

 cuueate, emarginate, and its angle- dentate. 

 Diameter 150-200 fi. 



A beautiful species and not rare, easily recognized by its 

 many and deep incisions ; it is variable in size and number of 

 subdivisions ; the latter range from twenty to forty in a semi- 

 cell. 



M. papili.iikka, Breb. Plate XXXI I. figs. 8, 9. 



Orbicular, with marginal gland-like teeth ; semicells five 

 lobed ; lateral lobe- dichotomously incised ; incisions narrow- 

 linear, the principal sinuses bordered by a row of minute 



granules. The end lobe about as wide as the others, and 

 emarginate, it- angles dentate. Endochrome is usually yellow- 

 ish or brownish green. 



Diameter 95-112 ft. 



Is found sparsely in shallow pools, but in a wide range of 

 many States. 



M. botata, (Grev.), Ralfs. Plate X X X 1 V, figs. 1, 2, 3. 



Orbicular, smooth; semicells five lobed; lobes dichoto- 

 mously incised with ultimate subdivisions variously bidentate 

 in different plants. End lobe somewhat exserted. The basal 

 lobes have each four subdivisions, and the intermediate Lobes 

 each eight. 



Diameter 200-250 p. 



M. denticulata, ( Breb.,) Ralfs. Plate XXXI V. figs. 1-8. 



Near the preceding, but separated by the usually obtuse 

 apices of the subdivision, often more oval form of cells, and 

 equal number of subdivisions in the basal and intermediate 

 lobes; polar lobe not exserted. Size about the same, but 

 many smaller varieties. Common. 



M. pimbkiata, Ralfs. Plate XXXVI, figs. 1-8. 



Large circular; semicells five lobed; dichotomously incised ; 

 end lobe cuneate with a broad shallow notch, or concave end, 

 and two or three mucros, or spines, at each angle. 



