138 CARBONIFEROUS AND PERMIAN FORAMIN1FERA. 



Planorbulina, for its modifications, by gradational variations, assume the characters of the 

 latter type. But the name Truncatulina is well understood as applied to a certain set of 

 specialised forms, and in the brief notice which is all that is needful in this place for a 

 type so slightly represented in the Carboniferous fauna it is undesirable to complicate the 

 terminology. 



It may be well to explain also that, although the synonymy of the Rotaline types 

 Truncatulina, Pulvinulina, and Cakarina has been given at some length, no attempt has 

 been made to render it exhaustive. The reader interested in such matters may turn to 

 Messrs. Jones and Parker's memoir ' On the Foraminifera of the Family RotaliiiBe' 1 for 

 much more extended references. 



The Carboniferous Truncatulina offer no points calling for special notice, the most 

 remarkable fact connected with them being their occurrence so low down in the 

 geological series. My friend Prof. W. K. Parker, on seeing the specimens, observed that, 

 except for alterations in appearance produced by age and by the process of fossilization, 

 he could detect nothing in their general features to distinguish some of them from the 

 forms now living in our seas a remark in which I entirely concur. 



TRUNCATULINA CARBONIFERA, nov. PI. VI, fig. 10. 



Characters. Test oblong, depressed, rugoso-punctate, irregular ; superior surface 

 complanate ; inferior, convex ; margin carinate. Segments few, inflated ; the 

 later ones relatively large. Sutures more or less limbate. Diameter, -^ inch 

 (0-42 mm.). 



A somewhat peculiar variety of Truncatulina differing in its cariuate margin, irre- 

 gular build, and inflated chambers, from any hitherto described. It is possible that the 

 specimen represented in fig. 10 may originally have had an additional chamber; and if 

 so, the raised line crossing the terminal segment is doubtless the remains of its shelly 

 wall, and not, as it appears, a mere exogenous growth. The species is somewhat larger 

 than the more regular form Tr. Boueana ; indeed, it approaches the common Tr. lobatula 

 in its dimensions. 



Distribution. In the Calcaire de Namur of Belgium, associated with Truncatulina 

 Boueana, very rare. 



1 ' Quart. Journ. Geol. Soc.,' vol. xxviii, p. 103. 



