40 FORAMINIFERA 



may be rather definitely determined from what is known of the 

 distribution of their contained genera in the present oceans. 



Pelagic foraminifera. The deposits of Globigerina-ooze as has 

 already been mentioned are composed very largely of pelagic 

 foraminifera. These are distributed by warm ocean currents 

 and their tests fall to the bottom in great numbers gradually 

 building up a sticky calcareous mud. Fossil oozes of this type 

 are found especially in tropical islands that have apparently 

 been raised during the Tertiary. The following 26 species have 

 been recorded as pelagic. All but one of these, Tretomphalus 

 bulloides, belong to the two families Globigerinidae and Globo- 

 rotaliidae. Tretomphalits becomes pelagic only in the adult 

 phase and is mainly found in tow net collecting about coral 

 islands. The early stages are apparantly bottom living and the 

 species are not therefore to be grouped with the oceanic pelagic 

 group. The following species are noted as pelagic : 



Globigerina bulloides d'Orbigny. 

 Globigerina dubia Egger. 

 Globigerina inflata d'Orbigny. 

 Globigerina cretacea d'Orbigny ( ?) . 

 Globigerina pachyderma Ehrenberg. 

 Globigerina dutertrei d'Orbigny. 

 Globigerinoides rubra (d'Orbigny). 

 Globigerinoides sacculife^^a (H. B. Brady). 

 Globigerinoides conglobata (H. B. Brady). 

 Globigerinoides helicina (d'Orbigny). 

 Globigerinella aequilateralis (H. B. Brady) . 

 Globigerinella digitata (H. B. Brady). 

 Orbulina universa d'Orbigny. 

 Hastigerina pelagica H. B. Brady. 

 Pulleniatina obliquiloculata (Parker and Jones). 

 Candeina nitida d'Orbigny. 

 Sphaeroidinella dehiscens (Parker and Jones). 

 Globorotalia menardii (d'Orbigny) . 

 Globorotalia tumida (H. B. Brady). 

 Globorotalia patagonica (d'Orbigny). 

 Globorotalia canariensis (d'Orbigny). 

 Globorotalia crassa (d'Orbigny) . 

 Globorotalia truncatulinoides (d'Orbigny). 



