geology; for it enables us to assert, with a confidence we could not otherwise have assumed, that the animals by which all fossil Nautili were constructed, belonged to the existing family of Cephalopodous Mollusks, allied to the common Cuttle Fish. It leads us further to infer, that the infinitely more numerous species of the family of Ammonites, and other cognate genera of Multilocular shells, were also constructed by animals, in whose economy they held, an office analogous to that of the existing shell of the Nautilus Pompilius. We therefore entirely concur with Mr. Owen, that not only is the acquisition of this species peculiarly acceptable, from its relation to the Cephalopods of the present creation; but that it is, at the same time, the living type of avast tribe of organized beings, whose fossilized remains testify their existence at a remote period, and in another order of things.[1]
By the help of this living example, we are prepared to investigate the question of the uses, to which all fossil Chambered shells may have been subservient, and to show the existence of design and order in the mechanism, whereby they were appropriated to a peculiar and important function, in
- ↑ A further important light is thrown upon those species of fossil Multilocular shells, e. g. Orthoceratites, Baculites, Hamites, Scaphites, Belemnites, &c. (See Pl. 44,) in which the last, or external chamber, seems to have been too small to contain the entire body of the animals that formed them, by Peron's discovery of the well-known chambered shell, the Spirula, partially enclosed within the posterior extremity of the body of a Sepia (Pl. 44; Figs. 1, 2.) Although some doubts have existed respecting the authenticity of this specimen, in consequence of a discrepancy between two drawings professedly taken from it (the one published in the Encyclopédie Méthodique, the other in Peron's Voyage,) and from the loss of the specimen itself before any anatomical examination of it had been made, the subsequent discovery by Captain King of the same shell, attached to a portion of the mutilated body of some undescribed Cephalopod allied to the Sepia, leaves little doubt of the fact that the Spirula was an internal shell, having its dorsal margin only exposed, after the manner represented in both the drawings from the specimen of Peron. (See Pl. 44, Fig. 1.)
