PROTOZOA. FORAMINIFERA. 19 



Miliola. (fig. 2, A D.) Test calcareous and por- 

 cellanous, multilocular, the chambers being coiled on an 

 elongated axis, each chamber forming half of a convolu- 

 tion. Sometimes all the chambers are visible externally 

 on both sides of the shell, at other times, owing to the 

 lateral prolongations of the chambers, only the last one or 

 two are seen, or it may be that more chambers are shown 

 on one side than on the other. The external features of 

 the shell consequently vary considerably, and on this 

 account the genus has been divided into a number of 

 subgenera. Trias to present day. 



Saccamina. Test arenaceous, compact, thick, formed 

 of a single spherical, pyriform, or fusiform chamber, or of 

 a number of chambers united end to end. Surface smooth 

 or nearly so. Carboniferous and living. 



SUB-ORDER 2. PERFORATA. 



The test is perforated by numerous minute canals for 

 the passage of pseudopodia ; it is usually calcareous and 

 vitreous, but sometimes arenaceous. 



Lagena. (fig. 2, F.) Test unilocular, calcareous, 

 vitreous, very finely perforated. Form spherical, ovate 

 or flask-shaped. A single terminal aperture, sometimes 

 at the end of a long neck ; rarely two apertures. Sur- 

 face smooth, ribbed, or spinous. Wenlock Beds to present 

 day. 



Nodosaria. (fig. 12, H.) Test vitreous, composed 

 of a number of chambers arranged in a straight line, and 

 separated by constrictions. Surface smooth or ornamented 

 with granules, spines, or ribs. Permian to present day. 



Textularia. (fig. 2, E.) Test vitreous, sometimes 

 arenaceous ; form variable, conical, pyriform, or cuneiform ; 



22 



