FAMILY 17. OPTHALMIDIIDAE 169 



Genus SILVESTRIA Schubert, 1920 

 Plate 53, figures 11-13 



Genoholotype, Nubecularia inflata H. B. Brady (not Terquem)=N. bradyi 



Millett 



Silvestria Schubert, Pal. Zeitschr., vol. 3, 1920, p. 166. 

 Nubecularia (part) of authors. 



Test with the early chambers similar to Calcituha, the later 

 ones inflated, irregularly coiled; wall calcareous, imperforate; 

 aperture rounded, irregularly placed. 



Recent. 



Genus SQUAMULINA Schultze, 1854 



Plate 20, figure 14; plate 21, figure 12 

 Genoholotype, Squamulina laevis Schultze 

 SquamuUyia Schultze, Organismus Polythal., 1854, p. 56. 



Test adherent, consisting of a single inflated chamber with 

 the wall calcareous and imperforate; aperture simple, on the 

 convex surface. 



Recent. 



In this family all the forms are planispiral at the beginning 

 except the degenerate ones such as Squamulina. There is a 

 direct line to the rectilinear series in Nodobacularia. From 

 Co7'nuspira to Planispirina by a division into chambers is but 

 a simple step, and from these to the other members of the sub- 

 family, the developmental stages are well shown in the micro- 

 spheric forms of the several genera. That no tooth develops 

 in the aperture makes this family at once distinguishable from 

 the Miliolidae where a toothed aperture is the rule. There are 

 parallelisms between the two groups but the development shows 

 the distinct character of such genera as SpiropthalTnidium and 

 Spiroloculina, or of Nodobacularia and Articulina. As no 

 toothed apertures are developed so also no cribrate forms occur 

 nor are labyrinthic forms found, the whole family consisting of 

 relatively simple forms. The character of incorporating 

 arenaceous material in the surface of the test is not taken up 

 by this family as it is in the simple genera of the Miliolidae. 



