6o 



MANUAL OF ZOOLOGY. 



in spite of the complexity and mathematical regularity of many 

 of their shells should be looked upon as the lowest forms of 

 the Rhizopoda, or even of the Protozoa. 



The pseudopodia in all the Foraminifera (fig. 7, b, c} are fila- 

 mentous and protrusible to a great length, and they possess 

 the singular property of uniting together in various directions 

 so as to form a kind of network, like an " animated spider's 

 web." (Hence the name Reticulosa applied to the order by 

 Dr Carpenter.) This property, however, is not peculiar to 

 members of this order, but is seen also in Actinophrys and in 

 the Thalassicollida, though to a less extent. Further, through- 

 out the entire network formed by the inosculating pseudo- 



Fig- 7- Morphology of Foraminifera. a Lagena vulgaris, a monothalamous Forami- 

 nifer ; b Miliola (after Schultze), showing the pseudopodia protruded from the 

 oral aperture of the shell ; c Discorbina (after Schultze), showing the nautiloid 

 shell with the foramina in the shell-wall giving exit to pseudopodia ; d Section of 

 Nodosaria (after Carpenter) ; e Nodpsaria hispida: f Globigerina bulloides. 



podia there is a constant circulation of granules in different 

 directions. This singular phenomenon is in many respects 

 analogous to the circulation of granules which is seen in 

 many vegetable cells, and it is believed by Dr Carpenter that 

 " the conditions of the two sets of phenomena are essentially 

 the same." 



The shells of Foraminifera may be classed in three divisions, 

 termed respectively the "porcellanous," the "hyaline" or 

 " vitreous," and the " arenaceous." The porcellanous shell is 

 quite homogeneous in its composition, is opaque-white when 



