ZOOLOGICAL CONSIDERATIONS. 







or similar extraneous bodies, more or less embedded in calcareous cement, the other 

 having opaque, porcellanous shells, of fine, texture. 



In the division comprising the perforate or porous-shelled forms the agreement is 

 less complete, as might be expected with the larger number of types to be accommodated 

 and the greater diversity in their characters ; but even in this the two classifications have 

 very much in common. 



Their general relationship will perhaps be best understood by a comparative table, 

 such as the following : 



VON REUSS, 1861. 



A. Foraminifera with non- 

 porous tests. 



A. WlTH ARENACEOUS TESTS. 



1. Lituolidea. 



2. Uvellidea. 



B. WITH COMPACT, PORCELLANOUS, 



CALCAREOUS SHELLS. 



1 . Squam ulin idea . 



2. Miliolidea. 



3. Peneroplidea. 



4. Orbitulitidea. 



B. Foraminifera with porous 

 shells. 



A. WlTH GLASSY, FINELY POROUS, 

 CALCAREOUS SHELLS. 



1. Spirillinidea. 



2. Ovulitidea. 



3. Rhabdoidea. 



4. Cristellaridea. 



5. Polymorphinidea. 



6. ' Cryptostegia. 



7. Textilaridea. 



8. Cassidulinidea. 



CARPENTER, PARKER, AND JONES, 1862. 



S ub-order Imperforata. 



Family G ROM IDA. 

 Family LITUOLIDA. 



Family MILIOLIDA. 



Sub-order Perforata. 



Family LAGENIDA. 



