I40 



NATURE 



[July 29, 1909 



potami, as indicated by its feeble pelvis, but less specialised 

 than the Sircnians. it would not be far from the truth 

 to say, from our present knowledge of the animal, that 

 Moeritherium is an offshoot of the Proboscideo-Sirenian 

 stock, with stighily nearer kinship to the elephants than 

 to the Sircnians. 



The distinctive peculiarities of Palseomastodon are that 

 its eyes are in the position typical among mammals, that 

 is, above the first true grinders. The reason that they 

 appear to be so far back is that the lower jaw is extended 

 unusually far forward. The upper jaws, on the other 

 hand, recede, practically terminating at the sides in the 

 very sharp, laterally compressed tusks, which at this stage 

 were chiefly developed as fighting or defensive weapons, 

 while only indirectly of value as feeding organs. It is 

 noteworthy that when the upper and lower lips are 

 restored in such a manner as to enable the animal to 

 -close the mouth, the upper tusks are so largely covered 

 that they are not especially prominent. 



In contrast with Mceritherium, the nasal bones and 

 openings deeply recede ; thus a very wide space is left 

 to be filled by a large retractile upper lip, which could 

 lundoubtedly be raised or lowered. The question now 



power of the anterior portion of the lower jaws, these 

 parts having receded and disappeared. The elephant thus 

 presents the widest possible contrast with Pateomastodon, 

 in which the most prominent part of the face is the pro- 

 jecting lower teeth and jaw. It is obvious that the 

 development of a proboscis took place step by step 'with 

 the recession and loss ol prehensile power in the lower 

 jaw. If Palzeomastodon had possessed an independent 

 prehensile proboscis extending beyond the line of the mouth 

 for the seizing of food, we cannot assign any function 

 to these large and much worn lower incisors. A more 

 probable view, therefore, seems to be that here presented 

 in the model of the head and mouth parts, which were 

 made directly upon a model of the skull itself. In the 

 stages between Pateomastodon and the M. (Trilophodon) 

 angustidcHs, the Lower Miocene elephant of Europe, the 

 lower incisors have begun to transform into tusks to be 

 employed in uprooting plants and smaller trees, just as 

 the upper tusks are used by elephants now. With this 

 change their prehensile function was gradually abandoned 

 and assumed by the upper lip, which thus began its slow 

 evolution into a freely projecting and prehensile proboscis. 

 All restorations contain a large element of conj'ecture ; 

 we shall certainly never know how ■ 

 these most interesting animals of the ' 

 Lower Oligoccne rivers of the Fayum 

 .nctually appeared, but the first rul" 

 of restoration is not to ho too much 

 influenced by kinship, but to adhere 

 to the evidence afforded by the hard 

 parts themselves. This rule has evi- 

 dently been broken by the writer in 

 attributing a small elephantoid ear to 

 Pala;omastodon. Unfortunately, there 

 is no means of even conjecturing the 

 shape of the ear of this animal, except 

 to exclude the small aquatic type of 

 ear which may be attributed to 

 Mceritherium. 



H. F. OSBORN. 



T//E HEALTH CONGRESS 

 AT LEEDS. 



Fig. 2.— Side view of the head of Mceritherium with the eye atid ear i;. 

 position of the nostrils is somewhat coniertural. Modelled by Mr. 

 direction of the writer. 



arises. How far had this lip begun to transform into a 

 proboscis? Was there a free projecting proboscis as re- 

 presented in several previous restor.itions? A negative 

 answer appears to be furnished by the structure and mode 

 of wear of the lower incisors. ' Together these form a 

 'broad, protrusive, spoon-shaped feeding organ, which is 

 invariably greatly worn on the upper surface and some- 

 what less at the ends. This worn upper surface seems 

 to prove that in the prehension of food the edge of the 

 upper lip was constantly pressed downward against these 

 teeth, thus, with the aid of fine particles of grit and 

 sand, which were occasionally taken in, causing wear. 

 In brief, the food appears to have been seized between 

 the upper lip and the spoon-shaped lower teeth. Palaeo- 

 mastodon was a browser, and this lip could be turned up 

 and retracted effectively to pull down smaller branches, 

 but there is no reason to suppose that it had the free 

 curling and independent prehensile power which charac- 

 ■terises a true proboscis. If we criticallv consider the 

 •theory of the animal possessing a proboscis of consider- 

 able length, we find it rests upon the idea of kinship with 

 the elephant rather than upon careful study of the mouth 

 ■parts themselves. 



_ If, now, we consider the elephant, we find that one of 

 Its many unique features is entire loss of the prehensile 

 NO. 2074, ■^'OL. 81] 



position. The form and 

 E. Christnian under the 



'X'HE Royal Sanitary Institute and 

 '- the Royal Institute of Public 

 Health combined this year, for the 

 first time, to hold under the auspices 

 of the Corporation and University of 

 Leeds a joint session. 



No more fitting person than Colonel 



T. W. Harding could have been 



selected to fill the presidential chair, 



who fills at the present moment the 



important office of chairman of the 



[ Royal Commission on Sewage Disposal. It is difficult 



within the space of a few paragraphs to present a com- 



, pre'ncnsive review of the varied topics which came up 



i for discussion in the different sections, and embraced 



( anything from the treatment of tuberculosis to that of 



[ trade effluents, and from the ventilation of cowsheds to 



the hygiene of the mouth. 



Although many of the views e.xpressed, especially in the 

 recently formed child-study section, were of a tentative 

 nature and the result of incomplete experience or of in- 

 dividual opinion, a striking feature ol the congress was 

 the earnestness displayed by those participating in it, a 

 remarkable fact when one considers how much of the 

 work connected with sanitary matters is self-imposed, 

 largely unofficial, and purely disinterested. 



It seemed appropriate that the president, an old Leeds 

 citizen, should have referred in his opening remarks to 

 the sanitary improvements of the town, which had nearly 

 halved the death-rate in fifty years ; but the greater part 

 of his address was devoted to a general survey of the 

 growth of public interest in and control of sanitation, and 

 the present-day problems of urban life. Among the 

 present-day problems he referred to the continued high 

 mortality from phthisis, pneumonia, and diphtheria, and 

 the heavy death-rate among children. Although the presi- 



