380 



THE MICROSCOPE. 



minute size for the most part, and consisting, as we 

 have already seen, either of one, two, or more con- 

 nected chambers. A jelly-like mass, or " sarcode," occu- 

 pies the chambers and their connecting passages ; and, 

 protruding itself both from the external aperture of 



Fig. 203. 



1, Section of Faujasina,: a a, radiating interseptal canals; 6, their internal 

 bifurcations ; c, a transverse branch ; d, tubular wall of the chambers. 2, 

 Rosalina ornata, with its pseudopodia protruded. 



the last chamber, and in many cases from the sometimes 

 numerous perforations in the shell-walls, extends itself not 

 only over the surface of the shell, but also into radiating 

 contractile threads or pseudopodia, and into gemmule-like 

 masses, which latter become coated over with calcareous 

 matter, and thus form additional segments of the animal. 1 

 " Foraminifera, indeed, are to be compared with the 

 other lowest orders of animals and of plants in the study 

 of their specific relations. In these several low forms of 

 creatures we have comparatively few species, but ex- 

 tremely numerous individuals, with an enormous range of 



(1) Among the more important works on Foraminifera, reference may be 

 made to D'Orbigny's Foraminifkres fussiles du Bassin Tertiaire de Vienna 

 (Autrihe); Schultze, Ueber den Organismus der Polythalamien, 1854; Car- 

 penter's and Williamson's Researches on the Foraminifera, Phil. Trans. 1856. 

 Also an excellent paper by Mr. W. R. Parker, in the Annals of Nat-ural History, 

 April, 1857. Specimens of Foraminifera may be obtained for examination from 

 the shaking of dried Sponges; but if required alive they must be dredged for, or 

 picked off the fronds of living seaweeds, over the surface of which they are 

 seen to move by the aid of a lens. 



