﻿142 CARBONIFEROUS AND PERMIAN EORAMINIEERA. 



would not be wise to attempt to describe in concise terms their special zoological 

 characters. They appear to represent a smaller species than any hitherto described, the 

 diameter of the figured specimen, which is the largest, being only ^ inch (0*65 mm.). 

 The margin has been strongly carinate and apparently rowelled, but it is partly broken 

 away and partly worn smooth. The less prominent parts of the surface show the 

 remains of the hispid or tuberculate condition, which is so common a characteristic of 

 the smaller varieties of the genus Calcarina. 



The drawings of one of the Carboniferous specimens, PI. VI, fig. 13, though of neces- 

 sity deficient in minute characters, will serve as a record of the occurrence of the form, and 

 render its identification easy should further research bring to light a more plentiful supply 

 of specimens. 



Distribution. — In the Calcaire de Namur, Belgium, very rare. 



Family, NUMMULINIDA, Carpenter. 



Genus. — Arch^ediscus, Brady. 



General Characters. — Shell convoluted, rounded, more or less unsymmetrical ; formed 

 of a non-septate tube coiled upon itself in a constantly varying direction. Shell-wall 

 traversed by very numerous, parallel, minute tubuli. 



The genus Archcediscus was established for a number of minute discoidal fossils, 

 structurally related to Nummulina, but differing in some important morphological 

 particulars. The range of modification observable in individual specimens pertaining to 

 the type is not great, and for the present there seems no need to recognise more than a 

 single specific form ; its detailed description and history therefore may best be given 

 under the subordinate heading. 



Arch^discus Karreri, Brady. PI. XI, figs. 1 — 6. 



Arch^ediscus Karreri, Brady, 1873. Ann. and Nat. Mag. Hist., ser. iv, vol. xii, 



p. 286, pi. xi ; — Report Brit. Assoc., Bradford Meet- 

 ing, p. 76 (abstract). 

 — — Id., 1873. Mem. Geol. Survey Scotland ; Expl. Sheet 23, 



p. 95, &c. 



