Reviews — Professor E. Ray Lankester's Extinct Animals. 515 



and Scorpions, occupy the field, and we see how forms adapted for 

 an aquatic existence may have their external leaf-like breathing 

 organs transformed into internal tracheae suitable for air-breathing 

 terrestrial dwellers. 



Fig. 2. 



Fig. 3. 



Fig. 2. — Eestored figure of the Scotch Silurian Scorpion {Palaophonus ITunteri), 



seen from below, to show the bases of the legs. 

 Fig. 3. — Eestored figure of the Silurian Scorpion from Gothland {Palceophonus 



nuncius), seen from above. 



One is astonished to find amid a changing world, in which whole 

 races of animals have appeared and disappeared over and over again, 

 that such simple creatures as king-crabs and scorpions date back 

 their ancestors to the Silurian period in Europe and America, and 

 still form a part of the living population of the world, the scorpions 

 dwelling in dry desert countries widely distributed over the old and 

 new world, the king-crabs along the Atlantic American seaboard, 

 and also in the Indian, China, and Japan seas. 



As to the size of animals, the lecturer reminds us that the 

 ancestors of the elephant, the horse, and other living types were 

 quite small forms; and that the hugest of huge reptiles, the extinct 

 Diplodocvs, 80 feet in length, is exceeded in bulk by the Eight 

 Whale, belonging to the highest existing class, the Mammalia. 



We predict for this book many readers, and, as a result, many more 

 visitors to the Natural History Museum, over which the author, 

 Professor Lankester, presides. 



