NATURE 



409 



THURSDAY, SEPTEMBER i, 1898. 



MORPHOLOGY OF VERTEBRATES. 

 Elements of the Comparative Anatomy of Vertebrates. 

 Adapted from the German of Dr. Robert Wiedershein 

 by W. N. Parker, Ph.D. Second edition. Pp. xvi + 488. 

 (London : Macmillan and Co., Ltd., 1897.) 



ELEVEN years have elapsed since we had occasion 

 to review in these pages the first English edition 

 of Prof. Wiedersheim's " Elements of the Comparative 

 Anatomy of Vertebrates," adapted and modified from 

 the first German edition by Prof. W. N. Parker. During 

 this interval zoology, like every other branch of science, 

 has been making steady progress, with the almost 

 necessary result that theories and views which were held 

 only a few years ago, have with increased knowledge 

 become untenable or required modification. Prof. 

 Wiedersheim has accordingly had on two occasions to 

 bring up his text-book to date by the issue of new 

 editions ; not that in the earlier editions extreme views 

 were set forth which have had to be abandoned, but 

 simply to keep pace with the natural growth of know- 

 ledge of the forms of animal life. It is not before it 

 was necessary that a second English edition has been 

 undertaken if the work was to maintain its place amongst 

 our comparative anatomy manuals of the day. 



It happens in most cases where further editions are 

 called for, that the author of the original work in his sub- 

 sequent issues not only brings them up to date, but also 

 considerably enlarges the modest dimensions of his first 

 edition by the introduction of new matter. This has 

 been the case with Prof. Wiedersheim's book, and in 

 preparing the work now under review. Prof. Parker has 

 had to select between the alternative of making a trans- 

 lation of a greatly enlarged German edition, and conse- 

 quently modifying the scope of the new English edition, 

 thereby bringing it into competition with the larger works 

 on the subject already in the field and within the reach of 

 English students, or of adapting Prof. Wiedersheim's 

 latest text, and thus maintaining the original character of 

 the English edition, which has proved to have a distinct 

 sphere of usefulness to the English student. Prof Parker 

 has, we think, been well advised in adopting the latter 

 alternative. But, notwithstanding his attempt to keep 

 down the size of the new English edition, it contains 143 

 pages more than the first edition. This is not, however, all 

 additional text, because in the present edition the bibli- 

 ography of the subject has received considerably more 

 additions to it than any other part, and instead of being 

 a short list of the principal monographs placed after each 

 section throughout the work, and when taken together 

 occupying not more than nine pages, it now forms an 

 appendix of 92 pages at the end of the book. Although 

 no one appreciates more than we do the advantages of a 

 rood bibliography, we consider that in a work like this 

 nder review, which deals only with the elements of the 

 abject, such a bibliography is entirely superfluous and 

 useless. While it would have been a useful feature in 

 a text-book of comparative anatomy of vertebrates to 

 which one would naturally go for references, it is quite 

 NO. 1505, VOL. 58] 



out of place in a work essentially for junior students. 

 Prof. Parker would, therefore, have been much better 

 advised to have kept this portion well within the limits of 

 the space assigned to it in his earlier edition. When the 

 portion of the book just referred to is left out of account, 

 the text proper shows an increase of little over 60 pages. 

 Some of these are occupied by new and additional illus- 

 trations, which are distinctly useful and an improve- 

 ment. As examples selected at random, we may mention 

 the new diagram inserted on p. 219, showing the shifting 

 of the lachrymal gland which has taken place in the 

 course of phylogeny, that on p. 240, of the development 

 of a tooth, and those illustrating the anatomy of the organs 

 of generation. There are also several new illustrations 

 which replace older and less perfect ones, amongst which 

 may be noticed those illustrating the anatomy of am- 

 phioxus, on p. 274, and the respiratory apparatus in 

 fishes, on p. 277. The number of illustrations is a 

 marked and useful feature of the work, and the manner 

 in which they have been executed by the publishers is 

 very commendable, as they show a great improvement 

 on those usually met with in English text-books. 



The arrangement of the text corresponds with that 

 adopted in the earlier edition, and begins with a general 

 introduction, in which the meaning and scope of com- 

 parative anatomy, the development, structural plan of 

 the vertebrate body, the main classification of the prin- 

 cipal vertebrate groups, and their gradual development in 

 geological deposits, and therefore in time are briefly ex- 

 plained. The comparative anatomy of the various organ- 

 systems is next described in the following order : the in- 

 tegument, the skeleton, the muscles and electric organs, 

 the nervous system and sense organs, the organs of nutri- 

 tion, respiration, circulation, excretion, and reproduction, 

 beginning in each case with those of the lower forms of 

 vertebrates and working up to the higher. A glance at 

 the first page is sufficient to show the correctness, as 

 regards it, of Prof. Parker's statement in his preface to 

 this edition, that much of the book has been entirely re- 

 written ; and this we have been able to confirm, from 

 examination of subsequent pages, is the case throughout. 

 He has also been at some pains to make the treatment 

 of the different sections more approximately equal, and 

 to deal with well-ascertained and essential facts rather 

 than take up space with doubtful theories and special 

 details. Hence we find that the views associated with 

 the name of Prof. Wiedersheim as to the derivation of 

 the limbs of higher vertebrates from the fins of fishes 

 have been judiciously omitted in this edition, and the 

 theories of Gegenbaur and others are not referred to, 

 presumably for the same reason. When the morphological 

 significance of a part is doubtful it is, we consider, far better 

 to state so openly, as has been done regarding the deriva- 

 tion of the diaphragm, where, after mentioning its mor- 

 phology in vertebrates generally, the author concludes 

 with the following remark : " The evolution of the 

 mammalian diaphragm is not yet thoroughly understood." 



The section of the comparative anatomy of the brain 

 and nervous system is considerably improved in the new 

 edition, both in the te.xt and the illustrations. The de- 

 scription of the suprarenal bodies no longer poses between 

 the description of the sympathetic nervous system and 

 the sensory organs, but is relegated to the end of the 



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