D PROTOZOA. 



SUB-CLASS I. KHIZOPODA.* 



Gymnomyxa, either naked or with a shell, the shell generally 

 calcareous and often pierced with fine pores for the e.rit of the 

 pseudopodia. 



Only in rare cases is the shell substance of a silicious nature ; 

 in all other forms it is membranous, with or without adhering sand 

 particles, or consists of a calcareous deposit in a basis of organic 



\ 



FIG. 4. MlUola ienera, with network Oi pseudopodia (after M. Schultze). 



matter. The shell is either a simple chamber, usually provided with 

 a large opening, or is many -chambered, that is, is composed of 

 numerous chambers arranged upon one another in a definite order 



* Besides D'Orbigny, Max Schultze, 1. c., compare W. C. "Williamson, "On 

 the recent Foraminifera of Great Britain," London, 1858. Carpenter, " Intro- 

 duction to the Study of the Foraminifera," London, 1862. Reuss, "Entwurf 

 einer system. Zusammenstellung der Foraminiferen," Wien, 1861. H. B. 

 Brady, "Report on the Foraminifera," Challenger Reports, 1884. J. J. Lister, 

 " Contributions to the Life-History of the Foraminifera," Phil. Trans., 186, 

 1895. 



