THE FOKAMINIFEEA OF THE ATLANTIC OCEAN 



NONIONIDAE, CAMERINIDAE, PENEROPLIDAE, AND 

 ALVEOLINELLIDAE 



By Joseph Augustine Cushman 



Of Sharon, Massachusetts 



INTRODUCTION 



This seventh part of the work on the Atlantic Foraminifera deals 

 with the Nonionidae, Camerinidae, Peneroplidae, and Alveolinellidae. 

 The Nonionidae are represented in the Atlantic by but three genera. 

 These are represented by numerous species, however, often very 

 abundant in dredgings and in shoal-water samples. The Camerinidae 

 are almost wanting in the Atlantic, but are abundant in the Indo- 

 Pacific. The Peneroplidae and Alveolinellidae are represented by 

 simpler, more primitive species in the Atlantic than in the Indo- 

 Pacific, but a few of the species are very abundant in the West 

 Indian region. 



Family 24. NONIONIDAE 



Test typically planispiral, more or less involute; wall calcareous, 

 finely perforate; aperture simple or cribrate, if simple, at the base 

 of the apertural face. 



This family is most abundantly represented in rather shallow 

 water. Of the three most abundant genera, ElpMdium, Nonion, 

 and Nonionella, ElpMdium reaches a great development in warm, 

 shallow waters, especially of the Indo-Pacific where the largest 

 species are found. It is also very abundant along the shores of 

 cold regions, but the species are usually much smaller. Nonion and 

 Nonionella are more abundant in a little deeper water as a rule, 

 but the various species are well adapted to geographic ranges as 

 are those of ElpMdium. 



The Palaeozoic genera, Crihrospira and Bradyina, may not belong 

 in this family, although they have much in common with the other 

 members. Orhignyna is limited so far as is known to the Cretaceous. 

 Polystomellina and Faujasina show peculiar modifications, a trochoid 

 form taking the place of the planispiral in the adult. 



The structure in most of the genera is fairly simple, but in the larger 

 species of Elphidium it becomes complex. 



