May 29, 1884] 



NA TURE 



99 



the habits of animals are recorded on personal observa- 

 tion they have evidently been accurately and carefully 

 noted. The author is a genuine naturalist with a thorough 

 love and admiration for animals, and in consequence he 

 possesses considerable power of understanding and appre- 

 ciating them. Secondly, the woodcuts are numerous and 

 for the most part excellent. A few, such as the big-headed 

 Gaur (Bos gaurus) on p. 530 and the musk-deer on p. 493 are 

 less successful, and it may be questioned whether a nylgao 

 can stretch itself into the gallop depicted at p. 477, but 

 the spirit of the cut last-named would atone for a worse 

 fault, and there is far more ground for admiration than 

 for criticism. As an amusing work, with good illustra- 

 tions, to which residents in India may have recourse for 

 the identification of the principal mammals, this volume 

 will probably find a ready place in the Anglo-Indian 

 library. For the determination of the smaller kinds, and 

 for a knowledge of the less known and more difficult 

 species, the student will do well to search elsewhere. 



W. T. B. 



NORTH AMERICAN MOLLUSC A 

 A Review of the Non-Marine Fossil M oilmen of North 

 America. By Charles A. White. (Washington : Govern- 

 ment Printing Office, 1883.) 

 THE Hon. J. W. Powell, the Director of the Geological 

 J- Survey in the United States, continues his valuable 

 contributions to scientific knowledge by the publication of 

 his annual reports ; and the volume which is now before 

 us forms part of the Report for 1881-82. 



This volume contains 144 pages, besides a full index, 

 and thirty-two lithographic plates. It is carefully and 

 modestly written, and the author candidly admits that our 

 knowledge of the subject treated by him is "very imper- 

 fect." The title of the work may be open to a slight 

 criticism ; and the word " inland " (" binnen " in German) 

 might be preferable to the negative expression " non- 

 marine," which is used by the author. 



The geological formations which are embraced in the 

 "Review" are the Devonian, Carboniferous, Jurassic, Tri- 

 assic, Cretaceous, Laramie, and Tertiary. With respect 

 to the Laramie formation, the author regards the group as 

 occupying a transitional position between the Cretaceous 

 and Tertiary ; it is remarkably fossiliferous, inasmuch as 

 a greater number of the species mentioned in the " Review " 

 come from that group than from any other. The total 

 number of North American non-marine or inland fossil 

 species and well-marked varieties appears to be 227, of 

 which 141 are found in the Laramie formation or group. 

 Twelve species are Palaeozoic, and of these no fewer than 

 seven species belong to the Pulmonibranchiata, and to the 

 families Limacido? and Helicidai, which are not only ter- 

 restrial mollusca, but undoubtedly air-breathers. Stro- 

 phites grandava of Dawson, from the Devonian formation, 

 is by far the most ancient land shell hitherto known to us. 

 In the face of these facts and in the absence of any facts 

 to warrant the conclusion of the author, how can we 

 reasonably agree with him " that molluscan life began in 

 the sea, and that all fresh-water and land mollusca 

 have been primarily derived from those of marine origin"? 

 Although no land mollusk has yet been discovered in the 

 oldest fossiliferous formation, it is evident that land and 



consequently terrestrial conditions must then and long 

 previously have existed, so as to account for the sedi- 

 mentary strata of which that formation consisted and for 

 the prevalence of Lingula and other shallow-water 

 Brachiopoda in the Silurian epoch. 



It is curious to notice that so many species of what are 

 usually considered marine Conchifera(Oj-/;va,/4 nomia, and 

 Mytilus) occur in the Laramie group, and one of A nomia 

 in the Cretaceous formation. This confirms the experi- 

 ments of Beudant and other naturalists, that many marine 

 gill-bearing mollusks can live either in their own native 

 and proper element or can gradually become accustomed to 

 a brackish and ultimately a fresh-water habitat. The author 

 also notes the " persistence through long periods of geo- 

 logical time of even the simpler types of non-marine mol- 

 lusks, after they were once established." And he remarks 

 with respect to the Gastropoda that, " although in geologi- 

 cal rank the Gasteropoda are so much in advance of the 

 Conchifera, the various families of the former seem to 

 have been developed as early in geological time as those 

 of the latter, and so far as we are now acquainted with 

 the history of the fossil non-marine mollusca of North 

 America, it appears that highly-organised land pulmonate 

 Gasteropods were introduced quite as early as any of the 

 Conchifers. Indeed from present indications we are led 

 to believe that the relations of the different classes of non- 

 marine mollusca to each other were much the same in all 

 geological epochs as they are to-day." The following is 

 also interesting : — " Notwithstanding the annual migration 

 of myriads of aquatic birds between the northern and 

 southern provinces of North America at the present time, 

 and doubtless also ever since it has been a continent, the 

 fresh-water molluscan fauna of those regions respectively 

 are still distinct." 



A few minor points of classification which are met with 

 in the present work will not be accepted by conchologists 

 without some hesitation, e.g. the extension of the so-called 

 family Rissoida (or more properly Littorinidce) so as to 

 include the genera Hydrobia and Bythinella, which latter 

 is a subgenus of Bythinia and belongs to the Paludinido?. 

 The families Pisidiida:, Physidce, Ancylido?, Vitrinida, 

 Arionidcr, Pupidcc, Succhiida?, and Viviparida seem to 

 be also superfluous. In every well-organised army there 

 ought to be a due proportion of men to officers of different 

 ranks. J. Gwyn JEFFREYS 



OUR BOOK SHELF 



Plant-Life. By Edward Step. Third Edition. (London : 

 T. Fisher Unwin, 1S84.) 



This is another attempt to give a popular description of 

 some of the more sensational parts of the science of 

 botany ; though the plan is disconnected, the general 

 idea of the book would not be bad, provided it were well 

 carried out. It is to be regretted that the author has 

 failed to realise that it is necessary to be accurate in 

 popular description. For instance, it is gravely stated in 

 italics that roots are never green (p. 29) ; we also read 

 that Ruscus acideatus " presents the remarkable appear- 

 ance of a flower growing in the centre of a leaf" (p. 94), 

 that the Cryptogams have no embryo (p. 211), and that 

 the Ricciacea: and Characeo3 have stomata (p. 212) ! On 

 p. 171 he mistakes intercellular spaces for cells in Isoetes, 

 which he classes under the Marsiliacea: (spelt Marcilearece, 

 p. 212; ; and on p. 165 we are informed that the elaters 



