March 31, 1887] 



NA TURE 



507 



forth the predominant characters of a given system of 

 parts. The chapters on Protozoa and the Leech may 

 be consulted as fair examples. In the latter, advantage 

 is taken of this method to force upon the student, some- 

 what pretnaturely, the fact that (p. 36) " the segmental 

 arrangement aftects in a marked manner the nervous, 

 excretory, and reproductive systems, and, to a less degree, 

 the circulatory and digestive organs," and the deduction 

 that " it appears to result from a definite arrangement of 

 parts which, in the ancestors of the leeches, were scat- 

 tered irregularly through the body, much as in Ftiscio/a" 

 (dealt with in the previous chapter). 



By way of contrast with its predecessor on the Frog, 

 this volume is shorn of much that is histological. In 

 the earlier work a special feature was made of this 

 branch, but here it by no means receives that amount of 

 attention which its importance demands. A start in this 

 direction might well be made with the lung-structure of 

 the bird and mammal, especially in view of the statement 

 made (p. 389) concerning the mechanism of respiration in 

 the former. 



The detailed descriptions of the various animals chosen 

 are, for the most part, exceedingly well rendered. A 

 slight ambiguity has crept in in one or two places, and 

 the descriptions of the vascular systems of the mussel 

 and snail might well be amplified. 



No portions of the descriptive te.xt stand more in need 

 of revision than those relating to the digestive glands. 

 These are, in Anodon, Helix, Astacus, and Amphioxus, 

 designated under the old term " liver.'' A certain amount 

 of justification is forthcoming in the last-named case, in 

 view of its blood-supply ; but in the three first-named 

 the striking results of recent research, which call for no 

 comment here, ought at least to be suggested in the term 

 " digestive gland " or " hepato-pancreas." While we 

 would see, thus, the substitution of a modern term 

 for one well-nigh obsolete, we would desire the with- 

 drawal of the terms " kidney " and " ureter " as applied 

 to the excretory organs of the Invertebrata. In the case 

 of the mussel, in which a portion of that which our 

 authors term "ureter," is glandular and secretory, the 

 terminology as restricted by them becomes misleading. 



Conspicuous among the novelties offered us are certain 

 words new to students' books. The volume is fully up to 

 date, and its authors are to be congratulated on having 

 produced the first book for students in the language, 

 which describes the receptaculum ovorum of the worm. 

 As regards pure nomenclature, it is worthy of note that 

 they have embodied, in describing the pterylosis of the 

 bird's wing (p. 386), that introduced by Prof. Flower so 

 recently as February 1886, in a lecture delivered at 

 the Royal Institution ; and necessitated by the splendid 

 work in which he is being assisted by Mr. R. S. Wray. 

 (The description of the barbules on the same page is in 

 error.) 



In dealing with the appendages of the insect, the 

 nomenclature customarily applied to the crustacean limb 

 is utilised. To this extension we heartily assent. On 

 turning to the crustacean itself, we meet with an innova- 

 tion far less deserving of support. Our authors, faithful 

 to precedent, reduce the body of the decapod crustacean 

 to twenty segments ; but in so doing they discard the 

 ophthalmic somite of their seniors, and press the telson 



into the service. This introduces a serious difficulty 

 when the nervous system is taken into consideration, and 

 a still more formidable one as concerns the homology of 

 the eye-stalk. That is passed over in comparative 

 silence, and, although we are not told so in as many 

 words, it is clear that they regard it as in no way serially 

 homologous with the appendages. The condition of the 

 visual organ in the lower Crustacea and other arthro- 

 pods, taken in conjunction with the facts adduced by 

 Brandt and others in the morphology of the insect's eye, 

 render it probable that the above view may turn out to 

 be correct. Nor must it be forgotten that Boas has 

 challenged {JMorpholog. Jahrhuch,\Qi\.v\\\.) the accepted 

 interpretations of the antennule. There are, however, 

 two sides to this question, and it is important to observe 

 that M. Alphonse Milne-Edwards has recently described 

 a decapod (Paliniirus penicillatus, Comptes reiidus, vol. 

 lix., 1864), in which one ophthalmite was for the most 

 part multiarticulate and antenniform. This remarkable 

 fact is the more striking in view of the reversion to the 

 antenniform type of certain post-oral appendages, seen in 

 Mastigoptts and Apseudes among the Crustacea, and so 

 well known in the scorpion-spiders ; whatever may be its 

 precise significance, it is clear that the question of 

 general homology of the eye-stalk, with which we are 

 here especially concerned, is far from settled. The 

 introduction of so sweeping a change into a book for 

 juniors without due comment is, under these circum- 

 stances, a false step, especially when it is considered that 

 the precise converse is stated in all other books current. 



Equally unjustifiable, in that it affects another debat- 

 able question, is. the statement (p. 379) that the bird's 

 pre-pubic process corresponds to the pubis of mammals. 

 Clear proof of this is not forthcoming. The student's 

 hand-book is not the place for such dogmatisms : if 

 asserted, they should be well qualified, and put as 

 alternatives. 



The retention of the old nomenclature for the bird's 

 air-sacs, with its atrocious " //w;vjaV" element, is disap- 

 pointing ; the substitution (p. 220) of " pericardio-r<r/(7OT/c " 

 for the well-tried pericardio-peritoneal canal of the fish is 

 as misleading as it is misjudged ; while that of " con- 

 Hcclivc " for the time-honoured commissure is, on the 

 whole, inadvisable. We live in a word-mongering age. 

 New terms which do not mark a turning-point in advance, 

 or at least the era of a new discovery, are stumbling- 

 blocks, unless introduced by way of replacing irrelevant 

 or absolutely fantastic precursors. Such is not the case 

 with those here under consideration. Our position is 

 somewhat that of the port-bound crew, in dread of being 

 stranded on their own beef-bones. 



Attention has been already directed to the diffusion 

 of the more general matter throughout the text. 

 This has been effected very successfully, and in well- 

 chosen language deserving of the greatest praise; but 

 we dissent from the method adopted. It will be generally 

 admitted that Hu.xley and Martin's " Elementary Biology" 

 dissipated for students of the subject, once and for ever, 

 the subtle " cram " ; and subsequent writers working 

 along similar lines have, as was to be expected, attempted 

 to improve upon the plan therein created, each after his 

 own lights. Messrs. Marshall and Hurst have aimed at 

 producing a work which they hope " may meet the wants 



