PROTOZOA OR SIMPLEST ANIMALS. 



9 



(Imperforata, Fig-. I), or liiVf, in additiou to the main aperture, the High Wall 

 wall of the shell perforated by uumeroius pores (Perforata, Fi}^. .'i). ^j^^= 

 Calcareous imperforate shells (see Family II.) have an opatjue white Gallery!* 

 poivellanous appearance, and perforate shells, in their early 8tii«<e.s, 

 a vitreous appearance (Families V. to X.). The shell may consist of 

 one chamber {Laijena, Family VII.), or of many, arranjred in linear, 

 spiral, or concentric series, or on each side of a middle line. 



In Globigerina, Ro/a/ia, &c. (Family Vlll. and IX.), all the 

 chambers of the " rotaliform " spiral are visible from above, Init 



Fig. 7. 



Shells of Glohigerina, showing lower ami upper surface. Mugiiilied. 



only the last coil from below. In XinnniNlifon (Family X. and 

 Introductory series) the last coil of the spiral wholly encloses all the 

 preceding coils. 



Although many of the specimens in the Case are very small, yet, 

 with the aid of the diagrams, the shape can frequently be made out ; 

 in some species the shells attain to relatively innnense proportions, 

 as Gijdoclypeus mrppnlerii (Family X.). from r«>rneo, with a thin 

 discoid shell over two inches in diameter. 



The Foramiuifera have played an imporlani pan in fi>rming 



