SCIENTIFIC LITERATURE. 



473 



SCIENTIFIC LITEEATUEE. 



POPULAR BOOKS ON EXTINCT 

 ANIMALS. 

 If ' Dragons of the Air,' by H. G. 

 Seeley, is not in quite so popular a vein 

 as its title might indicate it is none 

 the less a clear, comprehensive and in- 

 teresting account of that remarkable 

 group of reptiles, begging Professor 

 Seeley's pardon, known to science as 

 pterodactyls. No one is better qualified 

 than Professor Seeley to write of them, 

 as his acquaintance with these flying 

 dragons is of many years standing, and 

 he has made them the objects of spe- 

 cial study. He tells us that he has 

 attempted to show how a naturalist 

 does his work and illustrates the 

 methods of the paleontologist by 

 briefly comparing the various parts of 

 existing flying creatures with one an- 

 other and applying the information 

 thus gained to the study of the skele- 

 ton of the pterodactyls. Part by part 

 the various portions of this skeleton 

 are passed in review, and we are told 

 the more important variations found in 

 the widely varying members of the 

 group and between them and other 

 flying animals. Then, after a chapter 

 devoted to evidences of animals' habits, 

 from which the reader may learn how 

 the conclusions regarding the food, cov- 

 ering and flight of pterodactyls have 

 been reached, we are introduced to the 

 various species that have existed at 

 different periods of the earth's history. 

 In connection with this are given some 

 restorations of the more remarkable 

 of the dragons of the air, including the 

 extraordinary Dimorphodon with a 

 head bigger than its body. Accom- 

 panying these restorations are plates 

 showing the specimens on which they 

 are based, and the skeletons built up 

 from these specimens. Most of the 



figures represent the animals as run- 

 ning on all fours, an attitude that is 

 questioned by some of our paleontol- 

 ogists, notably by Dr. Williston, who 

 considers that they walked on the hind 

 legs alone and that the great Ornith- 

 ostoma in particular could not possibly 

 have used its fore limbs as legs. 

 The concluding chapters contain a 

 discussion of the relations and origin 

 of the pterodactyls and, from what has 

 been said in other parts of the book, we 

 are in a measure prepared to find that 

 Professor Seeley advocates a closer 

 affinity between birds and pterodactyls 

 than is usually accorded them. Most 

 anatomists will probably agreee in con- 

 sidering that many features of the 

 skeleton of pterodactyls, such for ex- 

 ample as its remarkable pneumatieity 

 are due to modifications for flight, but 

 the author considers that Pterodactyls 

 and Birds form two parallel groups 

 which may be regarded as ancient 

 divergent forks of the same branch of 

 animal life. But whether we accept all 

 Professor Seeley's deductions or not we 

 may safely accept his facts and we are 

 indebted to him for having placed so 

 much information within our reach and 

 for having given it in so readable a 

 form. 



'Animals of the Past,' by Frederic A. 

 Lucas, is more popular in its line than 

 ' Dragons of the Air,' and wider in its 

 scope, dealing with a number of the 

 more striking or more interesting of 

 extinct animals and especially with 

 those of gigantic size. Here, however, 

 Mr. Lucas's mission in life appears to 

 be to correct the widespread impression 

 that the animals of the past were so 

 very much larger than those of the 

 present. Some of the dinosaurs we 

 are told were the largest animals that 



