176 Reviews — Pocock's Carboniferous Arachnida. 



These and other species are figured in ten plates and fourteen text- 

 illustrations. 



In his conclusion Professor Seward remarks : " It is generally agreed 

 that the differences between Weal den floras and those from different 

 horizons in the Jurassic system are comparatively small. It may be 

 said without exaggeration that from the llhcetic and Liassic periods to 

 the end of the Jurassic period, including the Wealden, the vegetation of 

 Europe experienced no very striking or fundamental change . . . The 

 Culgower flora has many features in common with the Upper Jurassic 

 (Wealden) flora of Spitsbergen, the Wealden of England, Germany, 

 and other regions, as also with the older Jurassic flora of East 

 Yorkshire, which may be taken as a type of Middle Jurassic floras in 

 various parts of the world. As one would expect in a flora of 

 Kimeridgian age, we find an admixture of Wealden or Upper Jurassic, 

 Middle, and Lower Jurassic species." 



IRIE^IE-W-S. 



I. — A Monograph op the Terrestrial Carboniferous Arachnida 

 of Great Britain. By li. I. Pocock. Palseontographical Society, 

 in volume for 1910. 4to ; pp. 84, 3 plates, and 42 text-figures. 

 London, 1911. 



IT is a matter of common complaint among zoologists that fossil 

 animals, especially Invertebrates, are too often described by 

 writers who have an insufficient knowledge of recent animals and of 

 the literature referring to them. It cannot be denied that there is 

 sometimes ground for this complaint, but, on the other hand, it must 

 be admitted that there is justice in the palaeontologists' reply that 

 those who possess the necessary knowledge of recent animals can 

 rarely be persuaded to take up the difficult study of their fossil 

 remains. It is to be noted, further, that the scientific stud}* of 

 any group of fossils demands not only the broad outlook of the 

 morphologist, but also the minutely detailed knowledge of the 

 systematic specialist, since the necessary imperfections of fossil 

 remains often leave only the most trivial and superficial characters 

 from which to draw conclusions as to affinity ; and it is just the 

 systematic specialist who is least often ready to appreciate the scientific 

 importance of palaeontological research. 



Mr. Pocock is recognized as one of the foremost authorities on 

 recent Arachnida, and he has already made several noteworthy 

 contributions to our knowledge of some of the fossil representatives 

 of the group. Of the Monograph under review it is no exaggeration 

 to say that it places the study of the Carboniferous Arachnida on 

 a new footing, and it merits the attention of palaeontologists and 

 zoologists alike. 



In all, thirty-three species are described, but, as the author very 

 justly remarks, the species themselves are of very little importance in 

 the present state of our knowledge, and more attention is given to 

 discussing the characters and affinities of the Orders, families, and 

 genera to which they are referred. A large proportion belong to the 



