FOKAMINIFERA. 51 



Order III. Foraminifera. 



The Foraminifera are almost exclusively marine, only 

 a single well-defined genus, ffromia, is found in fresh- 

 water. 



GENUS GKOMIA. 



Animal spherical or oval, composed of granular proto- 

 plasm, with a large, central nucleus, and invested with a 

 homogeneous, chitinoid membrane. Mouth terminal, 

 and emitting copious streams of protoplasm, which flow 

 around the body and extend into numerous pseudo- 

 podal rays, freely branching and anastomosing, so as to 

 form an intricate net which exhibits an incessant flow of 

 granules along the filaments both outward and inward. 



Gromia terricola. 



Body spherical or oval, pale-yellowish or cream-colored, 

 more or less translucent. Shell chitinoid, thin, transpa- 

 rent, colorless or yellowish, with adhering sand and dirt. 

 Interior protoplasm white by reflected light, pale-yellow 

 by transmitted, granular, with fine oil-molecules, usually a 

 few clear vacuoles, and a large, clear or pale, granular 

 nucleus. Mouth obscure, emitting fine, granular proto- 

 plasm which breaks up into diverging and anastomosing 

 streams. An incessant circulation of granules is to be ob- 

 served along the filaments. Diameter, 112/4 to 120// ; 

 oval variety, 112/* long by 100// broad. 



Hob. With moss, and in crevices of pavements in 

 shaded places, in the City of Philadelphia 



