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THE AMERICAN NATURALIST [Vol. XLVII 



known and much of it is preserved intact. Only a few caudal 

 vertebras and a few spines of the vertebrae are unknown, which 

 for a fossil form is remarkable. In regard to the habits of the 

 animal the author says: 



Taking into consideration the very short and stout legs with their 

 broad flattened feet, the absence of claws, the elongate body and tail, 

 it would seem not at all improbable that Limnoscelis was more or less 

 at home in the water, though not strictly an aquatic animal. In much 

 probability it lived in and about the marshes on the mud flats. . . . 



From the press of the E. Schweizerbart 'sche Verlagsbuch- 

 handlung Nagle und Dr. Sprosser, Stuttgart, 1912, is a volume 

 entitled "Grundziige der Paleobiologie der Wirbelthiere, " von 

 0. Abel, professor of paleontology in the University of Vienna. 

 The work comprises an octavo volume of 708 pages with 470 

 figures and a photographic reproduction of the skeleton of 

 Cryptocleidus oxoniensis Phil, as mounted in the American 

 Museum. The work is dedicated to Louis Dollo, professor of 

 paleontology in Brussels. The work is divided into four sec- 

 tions as follows: (I) Geschichte und Entwickelung der Paleon- 

 tologie, (II) Die Ueberreste der fossilen Wirbelthiere, (III) Die 

 Wirbelthiere im Kampfe mit der Aussenwelt, (IV) Palaobi- 

 ologie und Phylogenie. The work is too extensive for an ade- 

 quate review in this place and it will suffice to say here some- 

 thing of the manner of treatment of the subject matter of the 

 volume. The usual systematic method of compiling a paleon- 

 tological work is not followed but the subject matter is pre- 

 sented from the standpoint of the adaptation of the animal to 

 its environment and is thus very refreshing to the zoological 

 paleontologists. Such items as the auditory apparatus of the 

 mosasaurs, the parietal organ, expansion of the thorax, dental 

 reduction in the pterosaurs, convergence and parallelism, 

 Todeskampf are taken at random throughout the work to indi- 

 cate the nature of the subject matter. Most of the figures are 

 copied from the works of other authors but a few are new. 

 Recent and extinct species are figured side by side when they 

 illustrate the same biologic phenomenon, as for instance on page 

 438, the recent Myliobatis aquila is illustrated side by side with 

 the Silurian Thelodus scoticus. On page 214 he states that the 

 present writer is mistaken in his correlation of the digits of 

 the Branchiosauria and that the second finger has wrongly been 

 regarded as the first. His reasoning is not adequate to sup- 



