54 



ZOOLOGY 



SEPT' 



condition it has a chitinous shell with a single narrow opening : 

 it multiplies by binary fission, and by multiple fission produces 

 gametes which copulate. 



f- 



> -*.**.- 



s-'^x, 



. = * i *^t 

 ' . * ^ ,*****- 



^s^ 



I.Saccammina 



3-Modosaria 



2.Lagena 



4.Frondicularia G.GIobigerina 

 s.sk. 



7. Discorbina 



O.PIanorbulina 



H.Nummulites 



FIG. :*7. Shells of Toraminifera. In 3, 4, and 5, a shows the surface view, and b A section: 

 8a is a diagram of a coiled cell without supplemental skeleton ; Sb of a similar form 

 with supplemental skeleton (.?. sk.) ; and 10 of a form with overlapping whorls ; in 1 la half 

 1 lie shell is shown in horizontal section ; b is a vertical section ; . aperture of shell ; 7 15 

 successive chambers, 1 being always the oldest or initial chamber. (After Carpenter, Brady, 

 and Biitschli.) 



Gromia (Fig. 36, 1} leads us to the more typical Foramiuifera. 

 The protoplasm of this form protrudes from the mouth (a) of the 

 chitinoid shell (sh.) and flows around it so that the shell becomes 

 an internal structure. The pseudopods are very long and delicate 



