FORAMINIFERA OF THE ATLANTIC OCEAN IQl 



dorsal side, from the ventral only those of the last-formed coil visible, 

 as the chambers extend into the middle at the umbilical region; 

 ventral side somewhat concave, dorsal side convex; sutures distinct; 

 wall thin and translucent; aperture at the end of the last-formed 

 chamber, usually circular. 



Diameter of Tortugas specimens up to 0.30 millimeter. 



The following notes were given in the Tortugas paper above 

 referred to: A comparison of d'Orbigny's figures in the Cuban 

 monograph will show that his Rotalina duhia really belongs to 

 Fischerina and allowing for reasonable differences in the figures, our 

 specimens from the Tortugas are undoubtedly the same as those 

 d'Orbigny had from the shore sands of Cuba and Jamaica. D'Orbig- 

 ny's specimens evidently did not show the aperture, as his figures do 

 not show this feature and his description refers to it with a question 

 mark. From the ventral side, Fischerina duhia is nearest to F. helix 

 Heron-Allen and Earland, which they described from the Kerimba 

 Archipelago. It is not common at the Tortugas. 



