﻿TROCHAMMINA. 



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external appearance, have been placed together under the single specific term Clima- 

 cammina antiqua. Some of them are long and flat, spathulate, tapering almost symme- 

 trically, as in Plate II, fig. 3 ; others are flat, carved at the commencement, with the 

 segments throughout set on obliquely like fig. 1 ; some have the early Textularian 

 chambers combined in a reversed manner, that is, with their broad faces in apposition, as 

 shown in figs. 4, 5 ; whilst occasionally instances are seen in which, probably from 

 irregular subdivision of some of the segments, the early portion of the test appears as 

 though triserial, or confused in its order of growth. Casts of the interior of the later 

 chambers have been found (figs. 6, 7), indicating that at times these must have taken 

 the form of a string of thick, round-edged, circular disks, regularly superimposed. 



A transparent longitudinal section (PI. II, fig. 8) shows an interior with confused 

 and imperfect septation ; the chamber-cavities more or less subdivided, and filled by 

 labyrinthic ingrowths of the shell-wall — the arenaceous structure of the investment, and 

 the cancellated form of the supplementary growths, being readily made out under a high 

 magnifying power, as shown in fig. 9. 



The compound character of the aperture may be observed either from the test itself, 

 as represented in fig. 4, or still better from the casts of the interior of the terminal 

 chambers before alluded to (figs. 6, 7), which of course are exact models of the 

 sarcode lobes of the animal, even to the little protuberances filling up the pseudopodial 

 apertures. 



Distribution. — Found in both the lower and higher series of the Carboniferous Lime- 

 stone (Scar and Yoredales) of England, and in the Lower and Upper Carboniferous 

 Limestone Groups of Scotland. Localities numerous, but the number of specimens 

 never very large. Doubtful specimens have been noticed in the Fusulina-limestones of 

 Russia. 



Genus. — Tkochammina, Parker and Jones. 



Nautilus (in part), Montagu, Pennant, Turton. 

 Webbina (in part), d'Orbiyny. 

 Operculina (in part), d'Orbiyny, Reuss, Brauns. 

 Cornuspira (in part), Reuss, Karrer, Schwayer, Terquem. 

 Orbis (in part), Strickland. 



Sekpula (in part), Geinitz, Morris, Bblsche, Schmid. 

 Foraminites (in part), Kiny. 

 Rotalin a (in part), Williamson, Alcock, Parfitt. 

 Spirilxina (in part), Williamson, Rupert Jones. 



Trochammina, Parker and Jones, Reuss, Carpenter, Karrer, Brady, Miller and Vanden Broeck, 



Robertson, Siddall. 

 Ammodiscus, Reuss, Bornemann, jun. 

 Involutina (in part), Terquem. 



