Reviews — Prof. A; Gaudnfs Enchainements. 519 



EEVIEWS. 



I. — Les Enchainements du Monde Animal dans les Temps 

 Geologiques. Fossiles Secondaires. By Albert Gaudry. 

 pp. 523. (Paris, 1890.) 



THE literature of Palaeontology bas been marked by a dearth of 

 any satisfactory popular handbooks, answering to the innumer- 

 able works by which the study of Zoology bas been encouraged and 

 advanced. There have been admirable scientific text-books suited 

 to the student, and any number of volumes discussing the relations 

 of fossils to cosmogonies and fads ; but there are very few books 

 such as the present, sufficiently simple to be intelligible to the 

 ordinary reader, and yet commanding the respect due to so well 

 known and distinguished a palaeontologist as Prof. Gaudry. 



The work commences with a chapter on the divisions of the 

 Mesozoic, with a tabulation of most of the palasontological zones — 

 and in some cases "zonules" — of the French deposits. The bulk of 

 the volume is occupied hy an account of the various groups of the 

 animal kingdom as developed in the Mesozoic era. These divisions 

 are sketched shortly and simply, and the leading points in their 

 structure and palasontological value well brought out. Thus the great 

 variability of the Foraminifera is illustrated by a number of figures 

 showing how Oolina might pass to a Cristellaria either through such 

 a series of forms as Nodosaria and Marginularia on the one hand, or 

 through Frowiicularia and Flabellina on the other. 



The author's principal conclusion seems to be that the corollai - y 

 to the acceptance of evolution is a great simplification of palasonto- 

 logical nomenclature. He points out in the preface that the attempt 

 to give separate specific names to each shade of variation would 

 simply result in the compilation of "catalogues sans limites ou 

 l'humaine faihlesse se perdra." He repeatedly asserts that the 

 width of specific range that is regarded as admissible in the members 

 of any group is simply dependent on the amount of work devoted 

 to that group. Many arguments in support of these views are 

 scattered through the descriptive portion of the treatise. As is 

 pointed out in the preface, the work is not a simple text-book of 

 palasontology, but an exposition of these ideas. Nevertheless the 

 short descriptions of the classes, and the extensive series of admirable 

 illustrations, will enable a reader to obtain a good idea of the 

 principal variations in any group. This is a book, moreover, which 

 will well repay perusal by more advanced students, as it is full of 

 most valuable and original suggestions. In fact, the most serious 

 fault to be found with the work is the way in which new ideas are 

 proposed without adequate illustration or discussion. Thus Prof. 

 Gaudry's theory of the origin of the Actiniaria from the Rugosa 

 through the Astreans, Turbinolidae, and Perforata, is compressed 

 with five illustrations into a page and a quarter. More space 

 might also be devoted to the suggestion that the old naturalists were 

 not so far wrong in allying the Foraminifera with the Mollusca ; 



