196 FORAMINIFERA 



FAMILY 23. POLYMORPHINIDAE 



Test spiral or sigmoid in the earlier stages, later in some 

 genera becoming biserial, uniserial, or irregularly branching; 

 chambers simple, not labyrinthic ; wall calcareous, very finely 

 perforate; aperture radiate except in the more degenerate 

 genera where there is a simple, rounded opening. 



KEY TO THE GENERA 



I. Test with the chambers in a closed spiral or sigmoid series at least in 



the early stages. 



A. Test not compressed, wholly spiral. 



1. Test rounded or elliptical with short chambers Guttulina. 



2. Test elongate, fusiform with elongate chambers. .. Pyrulinella. 



B. Test slightly compressed. 



1. Test spiral, becoming biserial Pseudopolymorphina. 



2. Test spiral, becoming uniserial Dimorphina. 



C. Test strongly compressed, becoming biserial PolyTnorphina. 



II. Test with the chambers in an open sigmoid series. 



A. Test elongate, chambers not reaching the base of the preceding 



ones, slightly involute Sigmoidella. 



B. Test ovate, chambers extending beyond the base of the preceding 



ones, strongly involute Sigmomorpha. 



III. Test irregular, of globular chambers with stolon-like connections. 



A. Free, very irregularly branching, stolons elongate Ramulma. 



B. Attached, chambers distinct, stolons short Vitriwehhina. 



Subfamily 1. Polymorphininae 



Test with the chambers in a closed spiral or sigmoid series 

 at least in the early stages, later becoming in some genera 

 biserial or uniserial. 



Genus GUTTULINA d'Orbigny, 1826 



Plates 26, figures 1, 2, 4 

 Genotype, by designation, PolyTnorphina (Guttulina) communis d'Orbigny 



Guttulina d'Orbigny, Ann. Sci. Nat., vol. 7, 1826, p. 266 (as a subgenus 



of Polymorphina) . 

 PolymorpJvhia (part) of authors (not d'Orbigny), s. str. 



Test rounded, spherical to fusiform; chambers spheroidal to 

 ellipsoidal or clavate, not at all compressed, arranged more or 

 less in an elongate spiral series so that they form generally a 



