i894. SOME NEW BOOKS. 387 



one picture. This is especially well seen in pi. x., devoted to the 

 Lagenae, and pi. xiii., devoted to the Globigerinse, and helps the 

 student to realise how intimately related all the so-called " species " 

 are, and how difficult it is to attempt to draw specific distinctions 

 when whole series of these lowlj^ organisms are obtained. Fornasini 

 has just published a paper on the Costa and Seguenza collections in 

 the Naples Museum {Mem. R. Accad. Set. 1st. Bologna, ser. 5, vol, iv.), 

 which were collected from the Tertiary marls of Messina. His paper 

 deals chiefly with the Nodosariae and Cristellariae, and the thred 

 beautiful plates of outline drawings leave nothing to be desired. 

 Dervieux has also published in the Boll. Soc. Geol. Ital., vol. xii., 

 part 4, a paper on the Tertiary Nodosariae of Piedmont, in which 

 64 forms are carefully described, and illustrated in one plate. There 

 should be no difficulty now in identifying the numerous Tertiary forms 

 of the genera, but students cannot be too strongly cautioned against 

 describing supposed new varieties without the most patient study of 

 existing literature, a study which, we think, is often neglected because 

 of the trouble and time required. 



The Study of Molluscs. 



Introduction a l'Etude des Mollusques. Par Paul Pelseneer. 8vo. Pp. 216, 

 figures. Reprinted [in advance] from the " Memoires de la Societe Royale 

 Malacologique de Belgique, torn xxvii." (1892). Bruxelles : H. Lamertin, 

 1894. Price 6 francs. 



Most works on elementary zoology are, as the author points out in 

 his preface, behind the time, because it is not in the power of any 

 single man to keep simultaneously abreast with the progress made in 

 all the various branches of zoological science. Pending the time 

 that such a work shall be produced, as the more advanced treatises 

 often are, by the co-operation of specialists in the several groups, the 

 student can frequently find much that he needs to know in mono- 

 graphs such as Graber's " Die Insekten," or Giinther's " Introduction 

 to the Study of Fishes," but no such work exists on the MoUusca, if we 

 except Coupin's that appeared in 1892. This last is, however, more of a 

 " cram book" than anything else, and was very much behind the time 

 even when it was issued, so that it is hardly to be seriously reckoned 

 with. Dr. Pelseneer's " Introduction," on the other hand, like all he 

 attempts, is thorough, and though there are points on which we 

 venture to differ from him, which are open to objection or criticism, 

 there can be no doubt of its great value to all malacologists as a 

 reference book, and as such it is cordially to be recommended. 

 Indeed, we only wish that the systematic conchologists (the variety- 

 mongers and mere collectors of shells may be left out of account as 

 past praying for) could be induced to master some of the principles here 

 so clearly set forth, since it could not fail to have a beneficial effect in 

 widening their mental vision, and so rendering their labours more 

 useful by imparting, to them at least, a tinge of true science. 



This Introduction is framed, of course, on a zoological basis, and 

 in some respects too exclusively so. The method of treatment is to 

 give a succinct account, first of the Mollusca as a whole, and then of 

 each class, or sub-class when that seems desirable, the sub-headings 

 being: — (i) Morphology; (2) "Ethologie," which the author defines 

 as the principal particulars concerning the conditions of existence, 

 in other words, the habits and mode of life, for which "Bionomics" is 

 a more appropriate term ; (3) BibHography ; and (4) Systematic 



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