Page:Geology and Mineralogy considered with reference to Natural Theology, 1837, volume 1.djvu/271

 VON BUH'S THEORY OF AMMONITES. formed around the base of the outer chamber, as affording points of attachment to the mantle of the animal, whereby it was enabled to fix itself more steadily within its shell. The arrangement of these lobes varies in every species of Ammonite, and he has proposed to found on these variations, the specific character of all the shells of this great family.