li^OEAMINIFERA OF THE GENUS SIPHONINA AND 

 RELATED GENERA 



By Joseph A. Cusioian 



Of Sharon, Massachusetts 



In 1850 Reuss erected the genus Sipho7iina and for its genotype 

 described the species JS. fimbriata Reuss from the Miocene of Austria. 

 jSiphonina is a genus related to Epistomina and others of the 

 Rotaliidae. Most of the recent and fossil specimens have been 

 referred by authors to the type species described by Reuss or to that 

 of Czjzek. Brady in the GJialleTiger Report placed Reuss' and 

 Czjzek's species under the genus TruTwatulina. For Truncatulina 

 the older generic name of GiMcides given by Montfort must be used. 

 In that genus the aperture comes over onto the dorsal side of the 

 test which is usually attached. The specimens referred to Siphonma 

 obviously can not be placed under Ttmncatulina or Cihicides. Reuss' 

 genus Siphonina is not only well described and the type species 

 of the Miocene of the Vienna Basin well known but the characters 

 are well fixed and of generic importance. Siphonina has been recog- 

 nized by later authors and its position is worthy of full recognition 

 not alone on the basis of nomenclatorial rules but because of its struc- 

 tural characters. 



In America the earliest known appearance of the genus is in the 

 Upper Cretaceous from which a species has been recorded by Mrs. 

 Plummer as Siphonina prima Plummer. This species has decidedly 

 primitive characters. Like the species of the Midway and Wilcox 

 Eocene, it is small and inconspicuous with the neck only slightly 

 developed. In the Claiborne and Jackson Eocene of America the 

 species are larger, and specimens often very abundant. Oligocene, 

 Miocene, and Pliocene species continued the specialization and highly 

 ornamented species occur. In the present oceans specimens are most 

 abundant in the West Indian region and particularly the Indo- 

 Pacific. 



In the Claiborne Eocene of the United States there was developed 

 a tendency to uncoil in the genus Siphoninella and another species 

 is living in the West Indian region. 



No. 2716.— Proceedings U ,S. National Museum, Vol. 72, Art. 20. 

 69357—21 1 



