5. 
to left coiling individuals of the widely distributed planktonic species, 
Globorotalia truncatulinoides, The effectiveness of this method of recog- 
nizing isochronous layers in groups of cores is shown by figures 2, 4-B 
and 5-B, 
Recent distribution of planktonic foraminifera. With Dr. K. K. 
Wang, Brooklyn College, work on charts showing present distribution of 
planktonic foraminifera in the North Atlantic is in progress. It is hoped 
to have the charts ready for publication in the near future. 
Knowledge of the present distribution of these species is essen- 
tial to correct interpretation of the vertical faunal changes in long cores 
in terms of water temperature and oceanic circulation. 
In order to be quite certain that the material described is truly 
Recent it is necessary to use top samples which have been relatively un- 
disturbed by the coring tube and which have not been permitted to become 
mixed in transportation to the laboratory. To this end it is customary to 
take short gravity cores in plastic liners by means of a corer attached to 
the trigger weight which releases the large piston corer. In description 
of the Recent fauna the tops of these short cores are used in preference to 
the tops of the piston cores. 
Tentatively, two of the conclusions of the work on present distri- 
bution of planktonic foraminifera are: 
1, It is generally true that planktonic foraminifera are tempera- 
ture indicators. But precautions should be taken when a species is widely 
distributed, and the area involved is of such great extent as' the Atlantic 
Ocean. For instance, Globigerinoides ruber is generally considered as a 
