NOTICES OF NEW BOOKS. 



239 



those who engage in monographic and faunistic work to any 

 large or comprehensive extent, and constitutes one of the many 

 evolutionary beacons which mark the course of developmental 

 zoology. 



Dr. Caiman considers that the possession of stridulating 

 organs by many Decapoda " is presumptive evidence that the 

 animals do have some power of hearing'' ; by some writers this 

 has been doubted, at least so far as regards stridulation in the 

 Arachnida. The problem awaits demonstration, which will pro- 

 bably prove to be of an affirmative nature. 



A strong feature in this volume is the historical account of 

 the work achieved and the views held on the different orders by 

 the older naturalists. If it is difficult in these days of extensive 

 publication to keep in touch with contemporary investigation 

 and results, it is also dangerous to ignore the views and con- 

 clusions (mistaken as many were) of those who preceded us. Our 

 present structures are built on many old foundations. 



