NATURE 



in 



THURSDAY, FEBRUARY 13, 1902. 



THE CAMBRIDGE SCHOOL, AND A 



ZOOLOGICAL TEXT-BOOK. 



Zoology, an Ekmeritarv Text-Book. By A. E. Shipley, 



M.A., of Cambridge, and E. W. McBride, M.A. (Cam'o.). 



D.Sc. (Lond.), of Montreal. Pp. 616 ; 349 text-figures. 



(Cambridge: University Pre5S,n 901). Price loj. 6^. net. 



YET another elementary text-book of zoology ! The 

 accumulation of facts in zoology during the last 

 quarter of a century has been so overwhelming, that it 

 becomes most difficult even to gauge the capacity of a 

 book like the present, which deals broadly with the 

 v.-hole field. Choice of subject-mitter is so wide, selec- 

 tion so difficult, that, in the endeavour to form an estimate 

 of such a work, the mere determination on the part of the 

 reviewer of a standard of comparison upon which to 

 judge it, is in itself an arduous task. Let it be said, how- 

 ever, that the senior author of the present volume has an 

 established reputation as a text-book writer, and that his 

 previous achievements have led us to expect a sometimes 

 thinnish mode of treatment. While in this we are not 

 disappointed, under the joint authorship a very creditable 

 book has been produced. 



There are twenty-three chapters in all, the first of which 

 is an " introduction " dealing with broad principles and 

 first definitions. The contents and style of this are such 

 as might be expected from a well-trained first-year man, 

 and are apt to create a false impression of the rest of 

 the book. This simplicity of treatment, however, is 

 intentional, and expressive of the authors' scheme — for 

 they tell us they have aimed at producing a book which 

 can " be readily understood by a student who had no 

 previous knowledge of the subject," and that the phrase- 

 ology of the later portions of the work is relative to 

 the earlier. Technical terms are explained as they 

 occur, with roots in original Greek, and with fuller 

 definitions where necessary. "Biogen" is introduced 

 as denoting the living molecule. Histology, embryology 

 and pah-Eonlology are intentionally placed at a discount, 

 the treatment of classification, and of adult structure "as 

 the outcome of function and habit," being the guiding 

 principle. The several sections of the work treat each 

 of selected individuals of a phylum, and the position and 

 interrelationships of these in the general scheme of 

 classification are for each section concisely stated, with 

 a short diagnosis, in an accompanying table — an 

 arrangement favourable to lucidity in the text, of which 

 the authors have made the most. 



Following the introduction are chapters on the 

 Protozoa, Coelenterata and Porifera. The Coelomata 

 are ushered in with an introduction special to them- 

 selves, and the leading Invertebrate phyla— viz. the 

 .Annelida, .A.rthropoda, MoUusca, Echinoder mata, and 

 Cha^tognatha — are in order dealt with. Seven chapters 

 are next devoted to the X'^ertebrata ; and there are 

 reserved for the four which conclude the volume the 

 Platyhelminthes, Nemertinea, Rotifera and Nematoda, 

 regarded as phyla which cannot be definitely asserted 

 . to be CLclomata. A decidedly novel arrangement this 1 

 but, under it, the Entoprocta (barely mentioned on p. 

 NO. 168 5, VOL. 65] 



286) appear to have escaped adequate recognition, 

 which is the more remarkable since the Chiistognatha 

 are accorded some three or four pages. 



As a whole, the book is well written and up to date, 

 and of the illustrations, those which are new are mostly 

 good, those borrowed well chosen. Diagrams are given, 

 especially where dealing with the circulatory system, 

 and some of those of the venous channels might well 

 be improved. There pervades the pages of the work a 

 freshness of style and unconventionality which render 

 them pleasant reading and attractive ; while, in the 

 frequent allusion to the commonest occurrences of daily 

 life and human affairs, the interest of the reader is 

 assured. The chapters on the Porifera and Annelida 

 may be cited as thin and inadequate, there being no 

 mention of the horny sponges, of the genus Oscarella, or 

 of the branchiate 01igoch;etes. Correspondingly slender 

 is the treatment of the " .-Anacanthini " and Insectivora, 

 the paragraphs upon which are miserably poor. Of defi- 

 nitions, that of the Cyclostomata may be instanced as 

 erroneous, in the non-recognition of the Bdellostomoid 

 forms possessed of more than seven pairs of gill pouches, 

 and the statements concerning the "bile-duct" and the 

 branchial basket-work (by comparison with p. 347), 

 Dohrn having shown the " extra-branchials " to be 

 extended gill-rays. 



The description of the pancreas as a mere "outgrowth 

 from the intestine" is insufficient, by non-recognition of 

 its compound origin, now demonstrated for all gnatho- 

 stomatous groups ; and, similarly, it is nowhere stated 

 that the pulmonary artery is now known to be in all its 

 forms a derivative of the fourth branchial arch. Nor is 

 there mention of the highly significant transitional con- 

 ditions of the heart (conus and its valves) occurring 

 among the Clupesoces. Again, a most important point 

 is lost in the ignoring of the circularjtype of the so-called 

 semicircular canals, and the invariably saccular innerva- 

 tion of that which is posterior. And, finally, to pass to 

 minor misstatements, we would remark that the forwardly 

 directed process of the chelonian shoulder-girdle is a 

 scapular derivative (proscapula) occurring only in these 

 creatures and the Plesiosauria ; that the epipterygoid 

 (columella) is not confined to the Lacertilia ; that the 

 prehallux of the Batrachia is not definitely proved to be 

 a digit homologous with the rest ; and that the bone 

 which suspends the ophidian mandible is most certainly 

 the supra-temporal. 



We are also of opinion that too full an assurance is 

 attached to the supposed quadripartite nature of the 

 " arcocentrum." This, as a vertebral theory, was 

 elaborated at Cambridge ; and we similarly find the 

 Balanoglossoid, also favoured of the Cambridge school, 

 set forth with all its best traditions — but why not 

 Cephalodiscus and Rhabdopleura as well ? They are 

 not even mentioned. 



One of the most noteworthy features of this book is the 

 tardy recognition of the facts of comparative embryology 

 and pakeontology, and it is the more remarkable that 

 the subordination of the former in a work written by two 

 Cambridge men, should have been decided upon, at a 

 time when embryological discovery of far-reaching 

 significance is being made known. In this book the 

 treatment of even larval forms is but casual and passing. 



