ART. 6 FORAMINIFEEA: POLYMORPHINIDAE — CUSHMAN AND OZAWA 13 



A quinqueloculine arrangement of chambers seems to be rather stable in the 

 family, as Guttulina is known from the Jurassic (?) and is rather common in 

 the Cretaceous, especially in the Upper Cretaceous, and very abundant in various 

 Tertiary deposits as well as Recent forms throughout the world. 



/. Chambers, in the early stage of the microspheric form, arranged in a quin- 

 queloculine series, later much overlapping, becoming apparently triserial, that is, 

 chambers added in planes more than 144° and less than 180° apart from one 

 another Globulina. 



g. Chambers invariably more or less elongated and embracing, arranged at 

 first in a somewhat quinqueloculine series, later becoming biserial Pynilina. 



h. Early chambers added in a quinqueloculine or biserial manner, later ones 

 becoming uniserial Glandulina. 



This group is of rather rare occurrence in the older Tertiary, but common fromi 

 the Miocene to the Recent. 



i. Early chambers in a quinqueloculine series, later each succeeding chamber 

 farther removed from the base, becoming biserial and in some cases uniserial. 



Pseudopolymorphina. 



The supposed Dimorphina is provisionally included in the present group. 



Pseudopolymorphina occurs in the Cretaceous, but not as commonly as in the 

 Tertiary and Recent. 



j. Test at least in the adult with the chambers added in planes slightly less 

 than 180° and more than 144° apart from one another, each succeeding chamber 

 farther removed from the base Sigmomorphina. 



This group is derived from Guttulina and is known only from the Tertiary 

 and Recent. 



k. Chambers arranged as those of the preceding group, but each succeeding 

 chamber embracing the earlier ones of its series. It is derived from Sigmoidina 

 and is known from the Tertiary as well as Recent Sigmoidella. 



I. Test with the early chambers arranged in a sigmoid series becoming biserial 

 or entirely biserial from the start. This is the most advanced group among the 

 Polymorphinidae and the chambers are added in planes 180° apart from one 

 another. It is only known from the Tertiary and Recent. It must be kept in 

 mind that even though it may be made up of an entirely biserial series of cham- 

 bers the test has an appearance of a slightly sigmoid arrangement of the chambers 

 continuing the shape of its ancestral development Polymorphina. 



BRIEF "notes on VARIOUS GENERIC NAMES GIVEN TO THE 

 POLYMORPHINIDAE 



There are not so many generic names given to various groups of 

 the Polymorphinidae. De Montfort's three genera, Arethusa, Misi- 

 lus, and Cantharus, are so very rough and ill drawn that they are 

 recognized with difficulty as belonging to the Polymorphinidae, not- 

 withstanding evidence of their having been copied from Soldani's 

 plates. Arethusa is given to the figure copied from Soldani's figure n n 

 (misprinted L L by de Montfort) in Plate 107, and Misilus is con- 

 sidered by Parker and Jones to be used for a globular fistulose form. 

 While Cantharus (seventy-fifth genus) is a very inaccurate copy of 

 Soldani (Testaceogr. pi. 107, fig. r r, misprinted p p by de Montfort), 

 Parker and Jones compared Soldani's figure with 'Polymorphina 

 ladea.' 



