Nov. 14, 1889] 



NATURE 



27 



may have served to grub up roots and tubers, and 

 tear off the branches of traihng plants. There is no 

 evidence that our living tardigrades had appeared among 

 the cave fauna of Brazil, where their place was supplied 

 by gigantic gravigrades, resembling the Megatherium. 



The results yielded by a careful study of the enormous 

 and varied materials obtained by Dr. Lund in his explora- 

 tions would appear, generally, to indicate that in post- 

 Pliocene ages the Mammalian fauna of Brazil was richer 

 than in recent times, entire families and sub-orders having 

 become extinct in the intervening ages, or at all events 

 greatly reduced as to the numbers of their genera and 

 species. This is more especially the case in regard to 

 the Edentata, Ungulata, Pachydermata, and Carnivora, 

 which still continue to be characteristic representatives 

 of the South American fauna. In two cases only there' 

 is evidence that species which are now exclusively 

 limited to the Old World once inhabited the American 

 continent. A far more marked difference between extinct 

 and living animals is to be observed in the western 

 than in the eastern hemisphere. Thus while the existing 

 Brazilian fauna comprises very few large animals, the 

 predominant forms being almost dwarf-like when com- 

 pared with their Eastern analogues, the post-Pliocene 

 Brazilian Mastodons, Macrauchenians, Toxodons, and 

 gigantic armadillos and tardigrades, may rank in size 

 with the elephant, rhinoceros, and hippopotamus, which 

 were their contemporaries in Europe at that period of the 

 world's history. 



There is no ground for assuming that the change in 

 the South American fauna was due to .any natural 

 cataclysm, and it would rather seem to be the result of 

 some regular and slow geological changes, which, by 

 affecting the then existing climatic relations, may have 

 ■disturbed the conditions of animal life, and thus brought 

 ■about the destruction, or deterioration, of the larger 

 mammals, which, according to Owen, succumb where 

 the smaller ones adapt themselves to altered conditions. 



It was not till near the close of his explorations that 

 Dr. Lund succeeded in finding human bones in such 

 association with fossil remains as to justify the conclu- 

 sion that man had been the contemporary in Brazil of 

 animals long since extinct in South America. Only 

 seven of the 800 lapas examined by him contained any 

 9iuman bones, and in several instances these were either 

 not associated directly with fossil bones, or there were 

 :grounds for suspecting that they might have been carried 

 ■into the caves in comparatively recent ages with the 

 streams that traverse them. In one of these, however, 

 the Sumidouro Lapa, remains of as many as thirty indi- 

 •viduals of all ages were found so intermingled with the 

 bones of the gigantic cave jaguar, Fclis prof opant her, and 

 the monster Cavia, Hydrochccrus sulcidens, together with 

 several extinct ungulates, that whatever may have been 

 the reason of their presence, there seems to be no ground 

 for doubting that primaeval man was contemporaneous 

 with these animals. 



The crania, of which admirably drawn illustrations are 

 given, are of a dolichocephalic type, characterized by 

 strongly-marked prognathism, and remarkable for the 

 excessive thickness of the cranial walls. The first com- 

 munication by Lund of his discovery of human remains 

 in the Lapa di Lagoa do Sumidouro was made (in 1840) 



in a letter addressed to Prof. Rafn, in which his fear of 

 being accused of recklessness in attaching too high an 

 antiquity to man in Brazil is shown by the pains he takes 

 to indicate every possible means by which these bones 

 might have found their way into the cave. Thus it re- 

 mained for his annotator, the late Dr. Reinhardt, whose 

 descriptive history of the caves and their exploration has 

 added largely to the interest of the volume before us, to 

 be the first to accept without reservation the co-existence 

 of man with extinct animals which, according to Lund 

 himself, occupied parts of South America more than 5000 

 years ago. 



The monograph treating of the human remains found 

 by Lund is from the pen of Dr. Liitken, the editor 

 of the present work, who also supplies a rcsumk in 

 French of the treatises contributed by his colleagues, 

 Drs. O. Winge and H. Winge, the former of whom 

 writes on the birds of the Brazilian lapas, and the 

 latter on the living and extinct rodents of the Minas 

 Geraes district. Besides these important contributions 

 to the work, the reader is indebted to the late Dr. Rein- 

 hardt for a detailed description of the situation and 

 geological character of the Brazilian bone-caves, and for 

 an interesting biographical notice of Dr. Lund. 



We learn from the preface that this collection of mono- 

 graphs owes, if not its publication, at any rate the com- 

 plete and elegant form in which it has been produced, 

 to the liberality of the directors of the Carlsberg Trust, at 

 whose cost, with the sanction of the Danish Royal Society, 

 it now forms one of those editions de luxe which have of 

 late years so largely enriched the scientific literature of 

 Denmark. The objection that may be advanced against 

 this, as well as others of the series, is that the writers 

 appear to be moved by an uncalled-for impulse to write 

 down to the level of the general reader, and to explain 

 the origin and progress of each special branch of natural 

 history they are concerned with. Such efforts to popularize 

 the, subject lead only to an inconvenient addition to the 

 bulk of the volumes, and are wholly at variance with the 

 scientific aim and object of such publications. 



HYDRAULIC MOTORS. 

 Hydraulic Motors : Turbines and Pressure Engines. By 

 G. R. Bodmer, A.M.I.C.E. " The Specialist's Series." 

 (London : Whittaker and Co., 1889.) 



THE essential detail which lifts the mere water-wheel 

 to the rank of a turbine consists, according to the 

 author, in some arrangement for directing the water over 

 the buckets in the most advantageous manner, instead of 

 allowing the water merely to follow its own course. Again, 

 in a water-wheel only a small part of the wheel is really 

 at work at a time, the buckets of the remaining part 

 being empty ; while a turbine is arranged, as a rule, with 

 a vertical axis, and all parts of the wheel are simultane- 

 ously taking their fair share of the work. In this respect 

 there is a great resemblance and analogy to the distinction 

 between the two chief instruments of ship propulsion by 

 steam— the paddle-wheel and the screw propeller. In the 

 paddle-wheel only a few of the floats act on the water at 

 a time ; while in the screw propeller, completely sub- 

 merged, all parts are equally at work, implying a great 

 saving of weight in the propelling instrument. Mr. 



