TWO GIGANTIC TYPES OP AEENACEOUS EORAMINIEERA. 
739 
interspaces filled with crystals of calcite, are obvious. Towards the right side 
the section comes to traverse the layers radially ; and we see the connexion 
of the labyrinthic structure of the successive lamellse by the radial processes, 
between which lie the interspaces filled with calcite. The solid floors sepa- 
rating the superposed lamellae from these interspaces are well seen at 
PLATE LXXVI. 
Fig. 1. Portion of a radial section of a specimen infiltrated with silex, showing the details 
of the structure of the concentric layers: — IH 1 , IH 2 , l 3 l 3 , IH 4 , four successive 
lamellae, showing their labyrinthic structure, built up on the impervious floors 
fl 3 ,^, and opening above into the successive interspaces int 1 , int 2 , int 3 ; 
at rp, idp' are seen the radial processes by which these interspaces are bounded ; 
and at t 1 , f are seen two of the radial tubes laid open longitudinally. — 
Magnified 70 diameters. 
Fig. 2. Portion of the preceding enlarged to 250 diameters, to show the arrangement of 
the component sand-grains. 
Loftusia. 
21. The extraordinary nature of the remains of Foraminifera discovered within the past 
few years in the Palaeozoic rocks of Canada, has in many ways affected previously received 
views concerning the testaceous Rhizopoda. In no respect is this so manifest as in the 
increased importance accorded to the whole group, on account of the size of its newly 
added members. On the first separation of the Foraminifera from the Mollusca, mi- 
nuteness was regarded as a distinctive character of the suborder ; and though it was 
found necessary to place the Nummulites in a systematic series, which consisted otherwise 
of microscopical organisms, they were looked upon as exceptional, in point both of mag- 
nitude and of complexity of structure. The discovery in recent times of specimens be- 
longing to larger types, such as those dredged off the coast of Borneo by Sir Edward 
Belcher, and subsequently described by Dr. Carpenter under the generic name Cyclo- 
clypeus *, scarcely excited sufficient attention to affect the general idea that the group 
was composed of animals of insignificant dimensions ; and it was not until the announce- 
ment and description by Dr. Dawson, of Montreal, in 1864, of Eozoon Canadense, that 
the views of Naturalists became modified as to the size attainable by a class of animals 
of so simple an organization. It is perhaps not too much to say that the controversy 
respecting the Protozoic, or at least the Animal, origin and characters of the remains of 
Eozoon, though eventually centering in questions of minute structure, would never have 
arisen at all, but for doubts initiated by the dimensions of the fossil. To those who have 
made the lower forms of animals their special study, the peculiar arrangement of the 
calcareous shelly layers on an acervuline plan of growth, already well observed in other 
types of Foraminifera, whilst it accounts for the irregular and asymmetrical external 
* Philosophical Transactions, 1856, p. 547. - 
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