﻿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 Rkuss, 1861. 



A. Foraminifera with non- 

 porous tests. 



A. With arenaceous tests. 



1. Lituolidea. 



2. Uvcliidea. 



B. With compact, porcellanous, 



calcareous shells. 



1. Squamulinidea. 



2. Miliolidea. 



3. Peneroplidea. 



4. Orbifulitidea. 



B. Foraminifera with porous 

 shells. 



A. With glassy, finely porous, 



CALCAREOUS SHELLS. 



1 . Spirillinidca. 



2. Ovulitidea. 



3. Rhabdoidea. 

 4>. Cristellaridea. 



5. Polymorphinidea. 

 (i. Cryptostegia. 



7. Textilaridea. 



8 . Cassidul in idea . 



Carpenter, Parker, and Jones, 1802. 



Sub-order— Imperforata. 



Fam ily — G rom i d a . 

 Family — Lituolida. 



Family — Miliolida. 



Sub-order— Perforata. 



Family — Lagenida. 



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