Page:Geology and Mineralogy considered with reference to Natural Theology, 1837, volume 1.djvu/259

 Rh the inner portion of the shell, (see Pl. 36 and 41.) 3d. A siphuncle, or pipe, commencing at the bottom of the outer chamber, and thence passing through the entire series of air chambers to the innermost extremity of the shell, (see Pl. 36, d. e. f. g. h. i.) In each of these parts, there are evidences of mechanism, and consequently of design, a few of which I shall endeavour briefly to point out.

The use and place of the shells of Ammonites has much perplexed geologists and conchologists. Cuvier and Lamarck, guided by the analogies afforded by the Spirula, supposed them to be internal shells. There is, however, good reason to believe that they were entirely external, and that the position of the body of the animal within these shells