November 2, i 905] 



NA TURE 



/ 



all' rations of coast-lines have modified the existing 

 ii much that, as in our own islands, Great 

 Britain and Ireland were, at no remote geological 

 time, joined to France, and a continental, instead ..I 

 an insular, climate prevailed here, with hotter 

 summers and colder winters, suited to the mammoth 



and reindeer which roved quite freely from land to 

 land. 



He explains what " fossils " are, and how the 

 sedimentary deposits, in which extinct organisms 

 occur, have been gradually laid down on the sea- 

 floor or along coast-lines. From minor changes he 

 illustrates those greater ones which took place 

 long since involving whole continents, so 

 that where London now is was formerly the 

 sea with marine shells and fishes, aptly re- 

 minding one of Lord Tennyson's lines : — 



" Oh Earth ! what changes hast thou seen — 

 There where the great street roars 

 Was once the stillness of the central sea." 



The story of the living and extinct 

 elephants is well told, and we get the latest 

 evidence of the progenitors of these very 

 ancient prehistoric beasts, the result of Dr. 

 Andrews's explorations and discoveries in the 

 Fayum, Egypt, which has carried their 

 ancestry back to the Eocene Palaeomastodon 

 and Meritherium. Near to the elephants 

 comes the wonderful Arsinoitherium, also 

 from the Fayum, with a pair of prodigious 

 horns on the front of its skull, a form of 

 animal which may possibly have had a short 

 proboscis like the tapir (Fig. i). 



The birds and reptiles come in for due 

 share of attention, and from their striking 

 forms they add largely to the attractiveness 

 of the illustrations. The comparison of the 

 wings of Pterodactvle, bird and bat is most 

 instructive, showing that reptiles, as well as 

 mammals and birds, enjoyed the power of 

 flight, as some also equally possess the power 

 ol swimming. Dimetrodon was undoubtedly a 

 swimming reptile (see Fig. 2). 



Fishes, Mollusca, scorpions and Crustacea, also 

 "sea-lilies," are dealt with in these lectures, and, as 

 might naturally be expected, these simpler forms of 

 life made their appearance far earlier in geological 



NO. Ibj9, VOL. 73] 



times 1I1. in the more highly organised creatures now- 

 living on our earth. 



More surprising still is it to find that the marine 

 king-crabs (Limulus) and the scorpions (the latter at 

 lirst aquatic, and afterwards terrestrial air-breathers) 

 which are met with in the Upper Silurian rocks in 

 America, Scotland, and 

 Sweden have survived all 

 the Old World changes of 

 land and sea, the king- 

 crabs being still found 

 living in the China and 

 Indian seas and on the east 

 coast of North Amei ii a, 

 and the scorpions have 

 spread over the di v 

 of North and South 

 America, Africa, and other 

 countries, and are so little 

 changed in appearani e 

 whole generations of other 

 animals having appeared 

 and disappeared entirely — 

 thai we might almost 

 imagine they would go on 

 for ever ! 



Although it would be 

 quite impossible for the 

 author or anyone else to 

 describe so vast a number 

 of groups of living and 

 extinct organisms in one 

 series of lectures and after- 

 wards to present them in book form with more than 

 200 illustrations in a single volume of 350 pages, at 

 least Prof. Lankester knows how to give, in an 

 attractive form, a vast amount of information agree- 

 ably, and to excite the interest of the merest tyro 

 (whether young or old) and awaken a desire in him 

 or her to learn more. Fortunatelv the author is also 



1) ; from the Upper 



=.— Probable appearance in life of the There 

 the Permian of Texas. As big as a larqe dog. 

 fitted for aquatic progression.) From Lankest 



morph Reptile, Dimetrodon, from 

 (It had a huge back-fin, evidently 

 r's " Extinct Animals." 



director of the Natural History Museum, where he has 

 abundant opportunities to add still more to our 

 personal knowledge of extinct animals. 



We give the book a hearty welcome, feeling sure 

 that its perusal will draw many young recruits to the 

 armv of naturalists and many readers to its pages. 



