220 Reviews — Br. C. W. Andreivs — 



the Natural History Department of the British Museum. Its execution 

 could not have been entrusted to more capable hands than those of 

 Dr. Charles W. Andrews, who deserves the warmest praige for the 

 high degree of skill and scientific learning which he has applied to 

 the completion of a task requiring close and protracted study to bring 

 it to so successful a termination. The publication of these two 

 volumes is the more welcome, as for the first time it allows us to 

 obtain an adequate idea of the enormo\is mass of extremely valuable 

 material contained in the Leeds Collection. It must be a matter of 

 no little satisfaction to Mr. Alfred N. Leeds to see brought together 

 in these volumes the valuable results thus obtained for palseontological 

 research bj' nearly fifty years of careful excavation and observation, 

 coupled with patient labour in restoring the specimens from in- 

 numerable fragments. 



The pi'esent volume is devoted to a second branch of the Plesiosaurs, 

 namely the Pliosauridae, and to the Crocodilia, which are particularly 

 richly represented in this collection. Following the method adopted 

 in the first volume, the author has initiated the description 

 of the various species belonging to these classes by an admirable 

 Introduction, in which he sets forth the main results of comparative 

 research into the relations of the Oxford Clay Reptilia with those of 

 earlier and later deposits. In the evolutionary history of the 

 Crocodilia nothing new has been ascertained, nor has much new light 

 been thrown on the problems surrounding the Sauropterygia. But 

 Dr. Andrews is led apparently by his studies for the purposes of the 

 compilation of this Catalogue to lay aside an earlier opinion that the 

 latter group is allied to the Rhynchocephalians, and now declares 

 himself an adherent of the view expressed by A. S. Woodward and 

 Williston that it is to the Theriodontia that we must look for their 

 origin. On the other hand, Dr. Andrews is unable to assent to 

 Williston's attempt to define the Pliosauridae, and notes certain 

 differences in the relations of the sphenoids to the pterygoids as 

 compared with the Cretaceous Trinacronierum, although in the 

 relationships of the frontals and parietals he finds the Pliosaurs to be 

 nearer akin to the North American than to the European Plesiosaurs. 

 This latter important modification of his earlier description of the 

 skull of the principal specimen of JPliosaiirus ferox has emerged 

 in the course of examination of a large number of examples of 

 Pliosaur skulls, particularly of Peloneustes. In addition to the new 

 species Simolestis vorax, other recent acquisitions by Mr. Leeds have 

 included a large Pliosaur, temporarily referred to Peloneiistes Evansi, 

 though it is found to differ so considerably from the genus, which 

 was created by Lydekker for the reception of PUosaurus philarchus, 

 that Dr. Andrews hints at the necessity of its ultimate assignment to 

 an entirely new genus. Highly interesting is the occurrence in this 

 series of some of the bones of a young animal. It is to be regretted 

 that no figure was incliided, as it would have given a far clearer idea 

 of the extraordinary changes which took place in such bones as are 

 known before the fully adult state was reached. Although the ribs 

 are well described, no account even is given of the ischium, which by 

 reason of its extraordinary massiveness, with additional thickness at 



