“The temporal and masseter muscles, by which the motion of the lower jaw is effected, are of immense size in carnivorous animals. The temporal muscle occupies the whole side of the scull, and fills the space beneath the zygomatic arch, the span and spring of which are generally an index of the volume of this muscle; while the extent and strength of the arch indicate the development of the masseter muscle. On the contrary, the pterygoid muscles, which aid the lateral movement of the jaw, are extremely small. The zygoma is of great size and strength in the carnivora; consisting of a long process of the masseter bone, overlaid by the usual process of the temporal bone, which is equally strong. The arch extends not only backward but upward, by the bending down of the extremity; the line of anterior declination falling precisely on the centre of the carnassière tooth—the point in which the force of the jaws is concentrated, and where it is most required for cutting, tearing, and crushing their food. In ruminants, the zygomatic arch is short, and the temporal muscles are small; but the masseter muscle on each side extends beyond the arch, and is attached to the greater part of the side of the maxillary bone. The pterygoid fossa is ample, and its muscles are largely developed. The arch is small in man, the temporal muscles moderate, and the force of the jaws comparatively weak.” _The Placenta._—Let us now turn to another important distinction between the carnivorous and non-carnivorous animals. Of these, perhaps the most important is the character of the _placenta_—one of the most distinguishing marks or characteristics of any species of animal. This subject has been so well and ably summed up by Professor Schlickeysen, in his “Fruit and Bread” (pp. 48-57), that I cannot do better than quote the main portion of the argument, as stated by this learned and able author. He says: “We now come to consider the peculiar structure, form and size of the placenta, as well as the exact method by which, through it, in different species of animals, the nourishment is effected. One of the most striking differences presented in placental animals relates to the method of union between the mother and the fœtus. There are two very distinct types of the placenta, and, according to Professor Huxley, no transitional forms between them are known to exist. These types are designated as follows:— 1. The non-deciduate placenta of the Herbivora. 2. The deciduate placenta, of which there are two kinds: (_a_) The zonary deciduate placenta of the Carnivora. (_b_) The discoidal deciduate placenta of the Frugivora.