Dr. John Evans's Address to Section C. 4i2\ 



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 Euminants, 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 mastodonts 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 

 paleeontological 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 Mons. Gaudry 

 is that to which I have already alluded — the development of the 

 complicated molars of most mammals. His view is that by a com- 

 parison with early and with foetal forms the probability may be 

 shown of these compound teeth being made up of what in earlier 

 forms were simple teeth — or, as he 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 Mons. 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 Sheppy, described by Professor Owen, 

 seems rather to be endowed with bony tooth-like processes in the 

 jaw, than actual teeth, and the head of the Argillornis from the same 

 locality is at present unknown. But the Hesperornis and Ichthyornis 

 from the Cretaceous beds of America possess veritable teeth, in the 

 one case set in a long groove in the jaw, and in the other in actual 

 sockets. Such intermediate, or, as Professor Huxley would term 

 them, intercalary forms, tend materially to bridge over the gap 

 which at first sight appears to exist between reptiles and birds, but 



