Bibliographical Notices. 3 1 9 



work is progressive in character, no that " the later chapters -will be 

 intelligiltle to the beginner only if he has read the earlier." 



The first twelve pages arc devoted to a brief but admirable intro- 

 duction, dealing with general principles. Following this come two 

 chajjters dealing with the several phyla from the Protozoa up to 

 Man, and these are excellent, being lucidly written and bringing 

 the essential characters of the several groups well to the front. 



"When the standard of excellence is so high it seems ungracious 

 to suggest that improvements are still possible ; but we venture to 

 think that in a future edition the chapter on the Protozoa might 

 be slightly extended, so as to give a little more s])ace to the Mycetozoa 

 and Ha^mamceba, and allow of a reference to Volvox and Pandorma. 

 "We have failed to find any allusion to the remarkable absence of 

 cilia in the Arthropoda, and would suggest that that portion of the 

 chapter on Birds dealing with the vexed question of classification 

 and the structure of the palate should be revised. 



The significance of the ccelom has received special emphasis by 

 the removal of the Platyhelminthes, jXemertines, Rotifera, and 

 Nematoda to the end of the book, since in all these this organ is 

 cons])icuou8 by its absence. By such transference the authors have 

 been enabled to trace a series of organisms, from the Ccclentera to 

 Man, all of which possess in some form or other this particular 

 organ. Having regard to the aims of this work, such a course can 

 readily be justified. 



The illustrations are very numerous, well selected, and unusually 

 well executed. 



Dragons of the Air. By 11. G. Seelet, F.R.S. Methuen & Co., 

 36 Essex Street, "W.C, London, 1901. 



Prof. Seelet is admittedly one of the greatest authorities in all 

 that concerns that ancient group of animals known as the Omitho- 

 sauria. For him these creatures have excited a quite peculiar 

 interest, which has lasted throughout the whole of his long scientific 

 career, and to-day he gives us, in a popular form, his conclusions 

 concerning their origin, development, habits, and afiinities, under 

 the title of ' Dragons of the Air.' 



A specially intimate knowledge of any given group of animals 

 frequently leads the investigator to conceptions which run more or less 

 counter to the generally accepted notions concerning that group ; 

 when this is the case, a serried array of well-marshalled facts 

 is usually suflicient to oust the old ideas and establish the new, 

 tradition being broken down by the force of the newly presented 

 data. 



Prof. Seeley's book is undoubtedly bristling with novelties, but 

 we very seriously doubt whether he will succeed in making a 

 single convert. Tlie restorations, which are numerous, appear of 

 themselves highly improbable, and we venture to doubt whether 

 the arguments brought forward for their justification will carrv 

 conviction. 



