6 PROCEEDINGS OF THE NATIONAL MUSEUM vol.77 



particular species. However, in this paper, attached forms are 

 separated from the others. 



ORNAMENTATION OF WALL 



Many species in the family have ornamented varieties. Orna- 

 mented forms are separated as a variety of smooth forms having the 

 same characters. When an ornamented form is described earlier than 

 a smooth form, the smooth form is taken as a variety. 



PHYLOGENETIC RELATION OF THE GENERA OF THE 

 POLYMORPHINIDAE 



The closeness of the relationship between the Polymorphinidae and 

 the Lagenidae is very marked. The wall is similar and especially the 

 terminal radiate aperture. However, the arrangement of chambers 

 is very different from anything seen in the Lagenidae. It is spiral, 

 triloculine, quinqueloculine, or sigmoidal, and in some advanced 

 groups it becomes biserial or uniserial. The most important problem 

 to make clear is how the spiral arrangement of chambers is derived 

 and what the relationship is between various genera with different 

 arrangements of chambers. That is the phylogenetic problem of the 

 Polymorphinidae. 



In order to study the phylogenetic relations of various genera of the 

 Polymorphinidae, the detailed examination of the arrangement of 

 chambers of any species is of utmost importance as in other groups of 

 the foraminifera. Excepting d'Orbigny, who gives end views of his 

 earliest species of the family in his Tableaux Methodique, no one has 

 figured end views showing an arrangement of chambers of any species 

 of the Polymorphinidae. 



This circumstance caused great difficulties in identification. Some 

 authors considered that the arrangement of chambers of Guttulina is 

 irregular or triserial, but we have examined very many species of 

 Guttulina and have not seen a single specimen having either an 

 irregular or triserial arrangement of chambers. We are convinced 

 that the arrangement of chambers in the Polymorphinidae is very 

 regular and that the family can be divided into several genera accord- 

 ing to the various arrangements of chambers as in other families of 

 Foraminifera. 



In order to discuss the relationships of various arrangements of 

 chambers, it is of interest to study some typical species of various 

 groups according to their geologic distribution. The geologically 

 oldest species of the Polymorphinidae hitherto recorded are Polymor- 

 phina avia and P. abavia, both described hj Ehrenberg from the 

 Ordovician of the neighborhood of Leningrad. These two species are 

 aggregations of glauconite, and there are some doubts about their 

 organic origin. 



