that which led to a similar specialisation in the cat tribe. Another most striking feature is to be seen in the condition of the incisors. Leaving out of consideration the mode of implantation and structure of the teeth—both confirmatory of the carnivorous hypothesis—there is one point which appears to me absolutely conclusive on the subject. Unless Owen’s figures are altogether unreliable, the lower incisors are quite unlike those of the herbivorous diprotodonts. In such typical forms as the wombat, the koala, the kangaroo, and the phalanger, though there are different modifications of the arrangement, we have the lower incisors meeting the upper, and forming with them an instrument for biting through a moderately tough, fibrous tissue, and even in the very small diprotodonts, so far as I am aware, the lower incisors always meet and work against the upper. But in _Thylacoleo_ we have powerful pointed incisors which do not meet, but overlap. Though technically incisors, they are not intended to incise, but to pierce and tear. Such powerful pointed and overlapping teeth, though easily explained on the theory that they were intended to kill and tear animal prey, were never surely provided merely to pierce succulent vegetables or ripe fruit. It might of course be argued that the incisors were used as weapons of defence, as apparently are the canines in the baboon; but against this idea is the objection that the incisors were put to some use which wore them down and blunted them more rapidly than would be the case if they were chiefly used on the rare occasions when the animal had to defend itself; and furthermore, were such the case, the temporals would not require to be greatly developed. “There is thus, in my opinion, no other conclusion tenable than that _Thylacoleo_ was a purely carnivorous animal, and one which would be quite able to, and probably did, kill animals as large as or larger than itself.” This opinion as to the carnivorous habits of _Thylacoleo_ is approved by Mr. B. A. Bensley, who has specially studied the Australian marsupials in a memoir recently published in the _Transactions_ of the Linnean Society of London. If it be correct, it reduces the net result of Flower’s investigations on this subject to a fuller realisation of the diprotodont affinities of the animal under consideration.