5o8 



NA TURE 



[March 31, 1887 



of those who desire to obtain a practical acquaintance 

 with the elements of animal morphology, and who find 

 the existing manuals insufficient for their purpose." It 

 is to be assumed that they have been especially mindful 

 of the needs of their own College, but the work also 

 covers most of the requirements for the elementary 

 examinations of other schools, and we presume the 

 authors would wish it a general circulation among pure 

 devotees. This said, we proceed to inquire into the 

 method of treatment, and find with much regret that, at 

 the outset, such deductions as are incorporated in the 

 text almost invariably precede the description of those 

 facts upon which they are based For example: on 

 p. 141, the alimentary canal of the crayfish — itself com- 

 plicated — is ushered in with the words that it is " a tube 

 running in a nearly straight line from mouth to anus. 

 Of this tube, the middle portion, or mesenteron, which is 

 very short, is alone formed from the primitive alimentary 

 tract of the embryo, and the 'liver' is an outgrowth of 

 it. The stomatodffium, or anterior portion of the canal 

 and the proctodasum, or hind portion, which together 

 form almost the whole length of the canal, are both 

 formed by invagination of the external surface of the 

 body ; and both have a chitinous lining which is con- 

 tinuous, at the mouth and anus respectively, with the 

 chitinous external covering of the body." Then follows 

 the detailed description. Again, the podical plates of 

 the insect are twice mentioned before the student is told 

 how to find them. The tympano-Eustachian passage of 

 the bird is (p. 414) similarly treated ; and here the 

 generalisation given should, if introduced at all, have 

 been rather inserted when dealing with the mammal, on 

 the supposition that, as can hardly be doubted, the 

 authors would have the student work over the animals in 

 the order of presentation. In such cases as the dogfish 

 skeleton (p. 198), the limbs of the mammal and bird 

 (pp. 287 and 376), and the enumeration of the differ- 

 ences between Amphioxus and the higher Vertebrata 

 (p. 168), the system is tolerable, by way of clearing the 

 ground and exciting interest. When, however, as in 

 the first-cited instance, the crowning triumph of the 

 student's labour is thus anticipated and his reward 

 forestalled, deduction on reflection upon his work falls 

 flat, and one of the chief aims of the whole system is 

 lost. This, to our thinking, constitutes the gravest defect 

 in this valuable work. 



In describing the rabbit's liver (pp. 306-7), the lobes 

 are rightly enumerated, but the student is not informed 

 upon what grounds the customary nomenclature is 

 adopted. In this, and one or two other instances, 

 explanatory clauses are needed, but not given. 



The illustrations are excellent, reflecting the greatest 

 credit upon all concerned, and artistic merit such as that 

 of Fig. 28 cannot fail to strike the reader. Fig. 27 is un- 

 necessarily complicated, too much having been attempted. 

 The beautiftil new figures of Amphioxus are especially 

 deserving of praise ; but more of them are wanted, in 

 order to do justice to the excellent description which they 

 illustrate. Comparison of this chapter with that on the 

 liver-fluke calls for this increase in number, in view of the 

 relative chances of the student's procuring specimens. 



Being mindful of the difficulties of preservation of 

 Amphioxus, it is to be regretted that, while full directions - 



are given for cutting sections, those for preservation, 

 which have led up to the splendid results incorporated in 

 this work, should have been omitted. This, the more so, 

 as the animal is to be obtained in the Channel Islands, 

 and is therefore within reach of the native student (a 

 fact which should be mentioned in the te.\t). 



In dealing with the higher vertebrates, the authors follow 

 one of their predecessors in first describing the skeleton. 

 We doubt the advantages of this system, especially as in 

 this work we have an "almost entire omission" of the 

 muscular system, held to be " of subordinate educational 

 value." The book, taken as a whole, is highly welcome 

 and most admirable. It is provided with an exceedingly 

 good index, and presented in a form demanding our 

 sincere thanks alike to authors, printers, and publishers. 

 Taking it, in conjunction with its predecessors, into 

 account, we have to congratulate the student of zoology 

 upon his accessions. This volume yields ample return 

 for the immense labour which its authors have bestowed 

 upon it ; it is well worthy of the school which they repre- 

 sent, and of its prototype above named. 



It is significant that the only typographical errors 

 which we have detected should be the occasional absence 

 of i and r. This fact might repay a careful research at 

 the hands of the printer. 



The authors state in their preface that " corrections or 

 suggestions from those who use the book will be very 

 gratefully received." Having dealt above with the more 

 important matters which occur to us, we append com- 

 ments on some of the more obvious among those of wholly 

 minor importance, noted in perusing the volume. 



Before proceeding to do this, we wish to call attention to 

 two matters of exceptional note : the first, the respiratory 

 folds of the lining membrane of the fish's mouth ; the 

 second, the attachment of the styloid element of the 

 rabbit's hyoid-arch to the paramastoid process. It is 

 indeed remarkable, seeing that these structures are of 

 such common occurrence, and that they have been pre- 

 sented to every native student of recent years, that there 

 is not yet a text-book in the language, or out of it for the 

 matter of that, in which they are described. This is the 

 more surprising in the case of the respiratory folds, in 

 consideration of their general development among the 

 gnathostomatous fishes. 



The Hydra. We cannot accept the description of the 

 supporting lamella as the " mesoderm " ; it is misleading 

 if not erroneous 



The Leech. There is no mention of the intermediary 

 nerve. 



The Earthworm. The description of the histology of 

 the nervous system needs amplification, especially as con- 

 cerns the distribution of the nerve-cells, by way of bringing 

 out the nature of comparison with the other types. The 

 account given of the blood-vessels is incomplete ; the 

 sub-intestinal trunk (described by Horst, NiederlanJ. 

 Tidschr. vol. xxxvii., and others) is not mentioned, thai 

 term being applied, in error, to the supra-neural vessel. 



We strongly dissent from the description given of the 

 oesophageal glands. Further investigation is necessary 

 before we can accept their subdivision into the tw.> 

 categories here proposed. By our contemporaries, as b\ 

 ourselves, much variation has been observed in then 

 number and relationships, and we have seen examples in 

 which all contained calciferous concretions and openen 

 into the gut. 



