vi 
OF SOUTH CAROLINA. 33 
Platynotus, Tsotelus, 
Trinucleus, Paradoxides, 
Ogygia, Brontes. 
Of the class Insecta, as they occur in the strata of England, Rev. Mr. Brodie has presented a 
beautiful memoir. In our country very few fossil insects have been found. 
Sup-KinGpom Mo.uusca. 
The soft and destructible nature of the animals of this sub-kingdom has left us in ignorance of 
much that it would be desirable to know, in relation to the organization and economy of many of 
the inhabitants of the fossil shells of extinct species, so abundant in all fossilliferous rocks. But 
we are left, in most cases, to infer their affinities from the analogy existing between the calcareous 
coverings of fossil and recent forms. In many cases this analogy is apparently very remote, and 
it required much patient research to discover it at all. In general, however, the shells are so well 
preserved that they may be studied with success; and from their great numbers in all countries 
they afford excellent guides to the Geologist in identifying rocks. 
Class Cephalopoda.—The Cephalopods derive their name from the apparatus which surrounds 
their heads, and which they use for the purpose of seizing their prey and holding’ it. This appa- 
vatus, which is highly curious, will be better understood by five minutes’ examination of the 
“squid,” so common along the coast, and which may be found in any shrimp-woman’s basket in 
the Charleston market, than by the most minute description. They are all characterised by highly 
developed heads, large eyes, and mouths armed with hard beaks. 
Those without exterior calcarious coverings have a bony internal appendage, and are also 
provided with an ink-bag, from which they eject a dark colored fluid that colors the water and 
favors their escape when pursued by enemies. These are further distinguished by having a gill 
on each side of the body. 
Prof. Owen has divided the class Cephalopoda into two orders, founded on the number of gills. 
To the first order, Dibranchiata, belong all the naked cephalopods, together with the living genus 
Argonauta, which is covered with a shell. The beaks of the animals of this order, together with 
the internal bone, are found fossil. The latter is represented by the fossil Belemnites, so common 
in the eretaceous formation. That this fossil is analogous to the internal bone of the recent naked 
Cephalopods is proved by the fact that it has been found in the same relation to the fossil ink-bag 
that it is known to have in the recent animal. 
The Belemnite is a pointed cylinder, composed of semi-crystalline limestone, having a radiated 
structure. At one extremity there is a conical hole in which there is sometimes found a chambered 
shell, called phragmocone; and although this is rarely found, the impressions of the septa may 
frequently be observed. It is provable that the genus Bellerophon belongs to this order. It is a 
small, involute shell, having, like Argonauta, but a single chamber. 
The order Tetrabranchiata includes those external chambered shells, which are perforated by a 
tube called siphunculus. The recent Nautilus represents this order. It has been divided into two 
groups, which have their types in the Nautilus and Ammonite, and are hence called Nautilide and 
Ammonitide. In the Nautilide the septa are not undulated on the margin, and the siphunculus 
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