﻿ENDOTHYRA. 



95 



shell-substance, and the margin is even and regular. The surface of the test is finely 

 granular. In some cases the granules are so minute and regular, as to be readily mistaken 

 for perforations, but the thickness of the shell-wall and its compact arenaceous texture 

 are readily seen in carefully prepared sections as represented in Plate V, fig. 6. 



Distribution. — In England Endothyra ammonoides is comparatively rare, though less 

 so in the Upper than in the Lower portions of the Carboniferous Limestone series. In 

 Scotland it is tolerably common alike in the Lower and Upper Carboniferous Limestone 

 Groups. Elsewhere I have no record of its occurrence. 



In Mr. Charles Moore's gathering from Keld Head in Wensleydale it was singularly 

 abundant, and the specimens very fine. 



Endothyra globulus (d' Eichwald) , PI. V, figs. 7 — 9. 



Nonionina globolus, 1 d' Eichwald, 1860. Letheea Rossica, vol. i, p. 350, Esp. 24, 



pi. xxii, figs. 17, a, b, c. 

 Endothyra globolus, Brady, 1873. Mem. Geol. Survey Scotland; Expl. Sheet 23, 



pp. 63, 95, &c. 



Characters. — Test discoidal, nearly symmetrical bilaterally, sometimes depressed at the 

 umbilicus ; consisting of several convolutions, each composed of ten or more segments, 

 the last convolution only being visible. Periphery thick and rounded, but little if at all 

 constricted at the sutures. Aperture, simple, crescentic. Diameter inch (0'65 mm.). 



It is very difficult to arrive at a satisfactory conclusion as to precisely what species of 

 Foraminifera are intended to be represented by d'Eichwald's figures bearing the names 

 Nonionina globolus and Nonionina rolula? respectively. The drawings are given with a 

 freshness and clearness characteristic of living specimens rather than of palaeozoic fossils, 

 and it is probably to their somewhat diagrammatic handling that the uncertainty in 

 identifying actual specimens may be attributed. But it can scarcely be wrong to assume 

 that the even, unconstricted, and rounded periphery, together with the depressed discoidal 

 form of the shell, are the characters intended to distinguish his Nonionina globolus. In 



' The specific term is so spelt in the ' Lethsea Rossica,' an obvious misprint, for which the necessary 

 correction is now made. 



2 I have entirely failed to identify Nonionina rotula, though all the Russian material sent to me by 

 General von Helmersen has been carefully searched for it. M. d'Eichwald states in a letter that his speci- 

 mens of Carboniferous Foraminifera were very few in number, and have long since been given away and lost 

 sight of, so that there is unfortunately now no means of verifying their characters. I have never seen 

 anything amongst the Carboniferous species resembling the sutural orifices represented in his drawing, 

 and the numerous apertures on the truncate face of the terminal segment are not suggestive of any affinity 

 with Nonionina. I cannot help thinking (and the affinity to Valvulina remarked by the author would 

 confirm the idea) that the specimen must have belonged to some species of Endothyra or of Lituola, in 



