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Show 362 PROF. W. H. FLOWER ON THE EDENTATA. [Apr. 18, prehension and mastication of food, they are quite as near, if not nearer, to the Anteaters. They may truly be regarded as intercalary-types, bridging over the gulf which now exists between them. The teeth are certainly those of the Sloths, even to the actual number in most genera ; but the diminution of that number in Ccelodon leads towards their total suppression in Myrmecophaya. In the lengthening of the anterior part of the skull in Meyatherium, but more strongly marked in Scelidotherium, the commencement of the Myrmecophaya type is clearly seen ; and that they had tongues longer and more protractile than those of existing Sloths (perhaps even prehensile, as Professor Owen suggests) is very probable. The vertebral column, ribs, sternum, and tail were far more Myrmecophagine than Brady-podine. In the scapula they possess a character which is shared by both Sloths and Anteaters but by no other mammal. The coracoid bone and the coracoid border of the scapula join over the coraco-scapular notch, converting it into a foramen. The recent discovery of clavicles in a rudimentary state in all three species of Myrmecophaga * adds another common character to the group, though perhaps not one of first-class importance. It must, however, be noted that in no species of Manis has any trace of a clavicle been found. The flattening of the femur, and development of a linear ridge along its external border, is common and peculiar to the Sloths, Anteaters, and Megatheres. The special characters of the manus in these three families are all derivations from a common type ; but in this portion of their organization the Megatherioids show their relationship with the Anteaters much more than with the Sloths. In the mode of setting the foot to the ground, and in the absence of claws upon one or more of the outer digits, the likeness is most surprising. The manus of the Pangolins, on the other hand, although presenting some superficial resemblances, is formed on a different type, in most respects more conformable to that which is normal among mammals ; but it has the peculiarity (which it shares with all known Carnivora) of connate scaphoid and lunar bones, and in the deep median clefts of the ungual phalanges it resembles Perameles among the Marsupials. Passing from this brief review of the osteological characters, we find in the arrangements of the arterial system of the limbs a close resemblance between the Sloths and Anteaters; and though the tail is so reduced in the former, its caudal artery is surrounded by a well-developed plexus, such as we could hardly account for, except upon the supposition that it were a remnant of a condition in which the tail resembles that of the Anteaters or Megatheres. In Manis, no retia mirabilia appear to be developed in connection with the arteries of the limbs-although one has been found, in at least one species, in the tail ; but it is also present in animals as far removed as the Spider Monkeys. A part of the organization to which it is natural to attach much importance in tracing affinities is that concerned in the reproductive function. The organs of both male and female Sloths and Ant- ' See W . A. Forbes, P.Z.S. 1882, p. 287. |