. The museum of natural history, with introductory essay on the natural history of the primeval world : being a popular account of the structure, habits, and classification of the various departments of the animal kingdom, quadrupeds, birds, reptiles, fishes, shells, and insects, including the insects destructive to agriculture . m, P/ias-culutherlum, Stereognalhus, Trionodon, and Phigian-lax, which have been exhumed in the upper Ouliticformation. The Mcgalosauriis,* or Great Lizard, was a terres-trial saurian, about forty feet in length. It seems toliave combined many of the characters both o
. The museum of natural history, with introductory essay on the natural history of the primeval world : being a popular account of the structure, habits, and classification of the various departments of the animal kingdom, quadrupeds, birds, reptiles, fishes, shells, and insects, including the insects destructive to agriculture . m, P/ias-culutherlum, Stereognalhus, Trionodon, and Phigian-lax, which have been exhumed in the upper Ouliticformation. The Mcgalosauriis,* or Great Lizard, was a terres-trial saurian, about forty feet in length. It seems toliave combined many of the characters both of theiguana and the monitor; the latter a lacertian reptilewliicli flourishes in tropical India and on the banks ofthe Nile. That it was carnivorous in its habits isevident from the complicated structure and arrange-ment of its teeth, which may be described as a com-pound of the knile, the sabre, and the saw. Wlien first protruded above the gum, the apex ofeacli tooth presented a double cutting edge of serratedenamel. In this stage its position and line of actionwere nearly vertical, and its form like that of the two-edged point of a sabre, cutting equally on each the tooth advanced iu growtli, it became curvedbackwards, in the form of a pruning knife, and the edgeof serrated enamel was continued downwards to tiio. Jaw of the Megalosaurns. base of the inner and cutting side of the tooth ; whilst,on the outer side, a similar tdge descended, but to ashort distance from the point, and tlic convex portionof the tooth became blunt and thick, as the back of aknife is made thick, for the purpose of producingstrength. The strength of the tooth was furtherincreased by the expansion of its sides. Had the ser-rature continued along the whole of the blunt andconvex portion of the tooth, it would, in this position,have possessed no useful cutting power; it ceased pre-cisely at the point beyond which it conld no longer beeffective. In a tooth thus formed for cutting along itsconcave
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