had. But the great carnivores had a covetous eye on Isacis, when it probably rolled itself up in its bristling armature, and, in full consciousness of a noli me tangere security, invited its enemy "to kick against the pricks"—in fact, to do his worst. And, doubtless, many a hungry feline, after recklessly accepting the invitation, got very badly worsted. As we shall see, there were little keen-toothed tigers then; but their acquaintance with Isacis always ended in disgust, as futile must have been each effort to get a dinner of hedgehog raw. Similar is the experience of our Adirondack catamounts in their attempts on the Canada porcupine. These fierce cats sometimes perish terribly from inflammation caused by the spines of the porcupine, which they are unable to extract.
The carnivorous animals were largely represented. Prof. Cope gives at least ten species. There are five genera of felines, or cats. One of these is quite small, being only half as large as the domestic species; another one, called Stibarus, for a cat, seems to have been a rather stout animal. Of these felidæ there are three genera which possessed remarkable saw-edged teeth, painfully suggestive of the carcharodont sharks. Accordingly, one of these is named Daptophilus squalidens, which, in plain though somewhat clumsy English, means the "sharklike-devouring lover." We are not from this to think of the grand Mogul, who loved his wives so well that he carved them up; but in metaphysical parlance the phrase must be taken subjectively, as of that absorbing passion where the subject loves to take his victim in—that is to say—one who is as voracious as a shark.
Another of these sabre-toothed tigers had its teeth very strong as well as sharp. "The incisors are very stout, and exhibit slightly curved conic crowns, with a serrulate edge on the inner face." These teeth are more suggestive of the trenchant cutlass than the fine sabre. Though not larger than the existing Canada lynx found in the Adirondack Mountains, this terrible tiger well deserves its fearful name—Machirodus oreodontis—the "mountain-like sword-toothed." Another of these carnivores, a new genus, is called Tomarctus. It had some relationship to the canines, but, if a dog, it was of very large size, as it probably equaled in this respect our native black bear. There were, however, true dogs then; and some of their remains were secured in the expedition. Their bones, associated with those of the rodents and insectivora, are quite numerous. One species, called Lippincott's Canis, was about the size of the coyote, or wolf of the plains. Other species obtained were larger than this; and others again were smaller. A Pliocene mastodon is mentioned, which carries the true Proboscidia far back in time. It is named Mastodon proavus, the specific name meaning "before one's grandfather."
Among these Colorado fossils, the ungulates, or hoofed animals, are very prominent. In the advanced classifications of the mammals, the ungulates are divided into the Perissodactyles, or those ungulates which
