526 report — 1878. . 



versely, and the dinoceras, somewhat allied to the elephant, but with six horns, 

 arranged in pairs, are as marvellous as some of the beasts seen by Sir John 

 Maundevile on his travels, or heard of by Pliny. But perhaps the most remark- 

 able series of remains ever discovered are those which so completely link the 

 existing horse with the eohippus and orohippus, and still farther extend the pedi- 

 gree of° the genus equus, which had already been some years ago so ably traced by 

 Professor Huxley. 



Of these American discoveries, as well as those made in the Tertiary beds of 

 Europe, M. Albert Gaudry has largely availed himself in his recent beautiful 

 volume on the links in the animal world jn geological times, a work which will 

 lon°- be a textbook on the inter-relation of different orders, genera, and species. 

 I am tempted to make use of some portions of M. Gaudry's own analysis of the 

 book, which he communicated to the Geological Society of France. Beginning 

 with the marsupials of the close of the Secondary and beginning of the Tertiary 

 period he shows that they are succeeded by such animals as the pterodon, the 

 hycenodon, the proviverra, and arctocyon, which present a mixture of marsupial and 

 placental characters, and to some extent justify a theory of the transition from one 

 order to the other. He next examines the "marine mammalia, and points out that, 

 so far as at present known, they make their appearance later than those of the 

 land, and that the examination of the pelvis of the halitherium tends to support 

 the idea of the mammals, such as the sireniaDS, which at the present day have no 

 hind limbs, being descended from terrestrial quadrupeds, for those limbs in the 

 halitherium are much less reduced than in its recent successors, the dugong and 

 manatee. After tracing the numerous links which are to be found between the 

 extinct and living pachydermata, he proceeds to show that, notwithstanding the 

 great distance between them and the ruminants, transitions may be seen. The 

 earliest ruminants were devoid of horns and antlers, but possessed upper incisors, 

 and by a comparison of the molars of different genera it may readily be conceived 

 how the large bosses of the omnivorous teeth of the pachyderms gradually shaded 

 into the small crescents of the teeth of the ruminants. At the same time the 

 passage from the heavy and complicated extremities of the limbs of the pachyderms 

 to the simpler and lighter feet of the ruminants can be traced. The history of the 

 horse family is also discussed, and the descent of existing proboscidians from the 

 mastodonts is shown to be probable, though the previous forms from which the nias- 

 todonts and dinotheria are derived are as yet unknown. Nor can the origin of the 

 carnivora as yet be suggested, though passages between the six existing families of 

 the order may be observed. In conclusion, M. Gaudry devotes a chapter to the 

 quadrumana, and thinks that palaeontological observations tend to diminish the 

 isolation in which these mammals now stand with regard to the other orders. 



One of the most important features insisted on by M. Gaudry is that to 

 which I have already alluded— the development of the complicated molars of most 

 mammals. His view is that by a comparison with early and with foetal forms the 

 probability maybe shown of these compound teeth being made up of what in 

 earlier forms were simple teeth — or, as he has termed them, denticules — which 

 have coalesced in the same manner as have some other parts of the normal bony 

 skeleton. In the compound teeth the denticules in some cases preserve their 

 original conical form, as in the pig tribe ; in others are elongated transversely, so as 

 by their junction to form ridges, as in the tapirs ; while in others, again, they are 

 drawn out into longitudinal crescents, as in the ruminants. Between these forms 

 there are of course, innumerable transitions. They do not, however, appear to me 

 to affect 'the importance of M. Gaudry's observations, which must be regarded 

 as of the highest value in all attempts to trace the inter-relation of different forms 

 of mammalian life. I must not, however, detain you longer on this subject, as I 

 trust that I have said enough to show the importance and interest of this book. 



The discoveries of early forms of birds with teeth do not come within M. 

 Gaudry's province ; but Professor Marsh has largely added to our knowledge of 

 these remarkable forms. The Tertiary Odontopteryx toliapicus from Sheppey, 

 described by Professor Owen, seems rather to be endowed with bony tooth-like 

 processes in the jaw, than with actual teeth, and the head of the Arqittwnis from 



