of the Lower Malm of Aargau. 57 
cylindrical tube, convoluted nearly in one plane. Convo- 
lutions few, partly embracing. Aperture large, sometimes 
margined, at the non-constricted end of the tube. 
Test finely arenaceous, the minute particles of sand im- 
bedded in a colourless or ferruginous cement, which generally 
hides the older part of the shell or forms a narrow fringe. 
Diam. 0°2-0°5 millim. 
The Swiss specimens approach the nearest to the subdis- 
eoidal variety from the English Permian *, and resemble in 
the mode of growth of the last convolutions 7. ¢ncerta (figs. 6 
and 7). 
A specimen with a fringe of shell-matter is also figured 
from the Carboniferous strata T. 
Most of the specimens from the transversarius-beds may 
be considered transitional forms between 7. zncerta and T. 
pusilla typ.t 
Distribution. In the lower beds A overlying the Callovian 
marls at Bozen and Biiren. Very rare. 
Trochammina filum, Schmid.§ (Pl. IIL. fig. 22.) 
In the varians-beds of the Bathonian stage, and chiefly in 
the Lower and Upper Argovian group, there occur simple 
arenaceous tubes, sometimes partly coiled up, of a somewhat 
doubtful nature, but which may possibly be assigned to 
L. filum. They consist of a cylindrical, thin, irregularly 
bent, partly convoluted, often slightly constricted tube, with 
a large rounded aperture, differing but little from similarly- 
formed siliceous tubes of different origin, with which they are 
associated in the sponge-beds of the lower transversartus-zone. 
Distribution. In the beds A of the Frickthal, the Upper 
Argovian rocks of the Geissberg, and the Upper Bathonian 
beds of Birmenstorf. Rare. 
Lrochammina constricta, sp. nov. (Pl. IV. figs. 23-26.) 
Test free, oblong, formed of a thin, regularly septate, and 
constricted tube of nearly uniform width. Convolutions few, 
sometimes slightly embracing, coiled up nearly in one plane. 
Aperture small, circular or crescentic, at the constricted end 
of the last chamber. . 
Shell-structure finely arenaceous, the numerous minute 
_* Jones, Parker, and Kirkby, Ann. & Mag. Nat, Hist. ser. 4, vol. iv. 
p. 386, pl. xiii. figs. 2-6. 
+ Brady, Monogr. Carb. Perm. Foram. pl. iii. fig. 4. 
t Brady, Joc. cit. p. 79. 
§ Schmid, Neues Jahrb. Min. 1867, p. 582, tab. vi. fig. 48; Jones, 
Parker, & Kirkby, foc. cit. p. 8389; Brady, loc, cit. p. 81, 
