THE FOKAMINIFERA OF THE ATLANTIC OCEAN. 



LAGENIDAE. 



By Joseph Augustine Cushman, 

 0/ tJie Boston Society of Natural History. 



INTRODUCTION. 



This fourth part of the work on the Atlantic Foraminifera deals 

 entirely with the Lagenidae, a family following in natural sequence 

 those families already considered in the three earlier parts. The same 

 general arrangement of data is here adopted. 



A study of the distribution, especially of the western Atlantic 

 Lagenidae, and the plotting of their occurrence, has shown that there 

 are very definite f aunal occurrences, as has already been noted in the 

 preceding parts, but it is perhaps even more marked in the Lagenidae. 

 There is very little similarity between the species occurring on oppo- 

 site sides of the Atlantic, even in the temperate regions. The fauna 

 developed off the coast of New England in cold water seems to be 

 most closly allied with that of Baffin Bay and Spitzbergen, while of 

 those species found in the warmer waters off the southern coast of 

 New England, practically none are found in typical form on the coast 

 of Europe. Those species which are characteristic of the Gulf of 

 Mexico and the Caribbean range northward to the coast of Georgia 

 or South Carolina, and in deeper water to Bermuda, but as a rule do 

 not occur along our Atlantic coast north of Cape Hatteras. As indi- 

 cated with the preceding families, the relationship of the Caribbean 

 and Gulf of Mexico fauna is with that of the Indo-Pacific. 



I have tried to give a reference to the various species found on the 

 eastern side of the Atlantic, but have made the reference brief as a 

 forthcoming work of Heron- Allen and Earland on the British Fora- 

 minifera will no doubt give greater detailed data in regard to such 

 species. 



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