gone too expose the fallaciousness of the principles upon which that work was based. Dr. v. Siebold has done much and well to reduce the number of German freshwater-fishes. We recommend a glance over the synonymy of the Dace (Squalius leuciscus) p. 203, to those whose tendencies carry them the other way-our author may have far in a few cases. Thus, for instance, nobody who has seen our Chub and its representative of the Continent, will agree with him, that both are of the same species. But there is no fear that other Ichthyologists will allow such questions as these to remain unsettled for long. Dr. v. Siebold gives detailed descriptions of those species only which are not perfectly known, whilst the commoner kinds, like the Perch, Pike, etc. are sufficiently characterized in a short diagnosis. His method of examining and describing a fish does not differ from that of previous writers, but whatever species is referred to, the account given of it will be found evidently to have been drawn from the author's own original researches, and shows that he has lost no opportunity of thoroughly acquainting himself with his subject. The history of each species is given as completely as possible. Our author fairly acknowledges where observations previously made, are only confirmed by him, and details the reasons which induce him to entertain different views from his predecessors. Even where he does not add any new fact, as for instance in the history of the Eel, his account will be read with pleasure for its perspicuity, and for the honesty with which he confesses where his own knowledge is incomplete. No other Ichthyological work has dealt in an equally prominent manner with two facts which, if only one half of the observations relating to them shall turn out correct, are of the greatest importance in distinguishing the different species, viz, hybridism, and sterility. The author gives it as his opinion that hybridism is by no means of rare occurrence among fishes, although the cases which he considers as more or less established, belong to one family only, that of the Cyprinoids. They are five in number: 1. Carpio kollarii, Heck. 2. Abramis leuckartii, Heck. Hybrid between Leuciscus, sp? 3. Abramis abramo-rutilus, Holandre Scardinius erythroph thalmus, L. 4. Leuciscus dolabratus, Holandre 5. Chondrostoma rysela, Agassiz Alburnus lucidus Squalius cephalus The least doubtful is the first, but then we must not forget that this Carpio kollarii is the produce of two domesticated species, viz. the Carp and Crucian Carp, and therefore that this instance per se only proves that hybridism is possible in this class of vertebrate animals. The other instances certainly need confirmation: and nobody who looks over the list given above, will fail to remark that in every case, the fishes said to be the parents of these hybrids, are referred to two different genera, and are thus not the offspring of closely allied species of the same genus, as we should expect a priori.* Surely there is something wrong here! Either the genera are based upon merely specific characters, and not entitled to that rank in our system, or the explanation of the origin of those hybrids, and even their hybrid nature itself becomes a matter of great difficulty. Dr. v. Siebold himself is evidently wavering: for whilst he asserts his conviction that the fishes are hybrids, he not only prefixes to their descriptions the heading "characters of the species," but actually forms two new genera, viz. Abramidopsis for A. leuckartii, and Bliccopsis for A. abramo-rutilus! Not even Heckel or Bonaparte would have been guilty of such an inconsistency as this, and we can only partly account for it from the author's former studies of the lower classes of the animal kingdom, where many genera are founded upon larval forms. The question whether these hybrids are fertile, is not solved; but their sexual organs were found to be fully developed. The discovery of the author, that there are individuals of certain species, especially of the Salmonoids, but perhaps of all other families, which remain sterile throughout their life, assuming with age a form very different from that of individuals with the sexual organs normally developed, is scientifically of the greatest importance, and will engage Ichthyologists for some time to come. A speedy confirmation of it is the more wanted, as should these barren fish occur in considerable numbers, the question would assume a practical Ornithologists who call to mind the hybrids between different species of ducks, will, perhaps, not find any thing surprising in this, but a genus in Ichthyology is generally more comprehensive than one in Ornithology. bearing; for normally developed fishes feed little during the time of propagation, and consequently are lean and unfit for the table immediately afterwards, whilst a sterile individual continues to feed, and therefore remains in season throughout the year. A systematic index with short diagnoses, and three synoptical tables showing the horizontal and vertical geographical distribution of the eighty species described, and their spawning seasons, conclude a work which has done a great deal to expiate the sins of its predecessors, and which we particularly recommend to the Ichthyologists of this country-not to be copied from, but to be imitated. V.-HUXLEY AND HAWKINS' OSTEOLOGICAL ATLAS. AN ELEMENTARY ATLAS OF COMPARATIVE OSTEOLOGY. By Professor Huxley, F.R.S. and B. Waterhouse Hawkins. Williams and Norgate, 1864. THE object of this work, as stated in the introductory note, is to aid students in comprehending the general arrangement, and some of the most important modifications of the bony framework of the Vertebrata. The drawings are executed by Mr. Waterhouse Hawkins: the very important task of selecting, arranging, and naming the parts of the objects figured is Professor Huxley's share in the work. There are twelve plates, folio size, drawn on stone, containing on the average about twenty figures in each plate. The first shows the structure of the skull of four of our commonest domestic animals, belonging to as many different orders of mammals-viz., the dog, pig, horse, and sheep, illustrated by views of the upper, under and lateral surface, as well as by a median longitudinal vertical section. Comparison of the different objects both in this plate and in most of the others in the work is greatly facilitated by the figures being all drawn of the same absolute size, and also by the names of the different elements being marked on the plate, so that no turning-overpages to refer to a description is required. The second plate shows in the same manner the most characteristic differences between the skull of man, and of the several species of apes, both of the Old and New World. In the third and fourth plates are figured the crania of some of the lower mammals, of birds and of reptiles; the fifth is devoted to the skulls of fishes; the vertebræ of the different regions of the spinal column of a mammal (wolf), a bird (ostrich), and a reptile (crocodile) are compared and contrasted in the sixth and seventh plates. The illustrations of the structure of the vertebræ are continued in the eighth plate, together with views of some of the principal modifications of the hyoidean apparatus in the mammal, bird, reptile, and fish. The remaining four plates are devoted to the osteology of the extremities. Two of these contain views of the terminal division of the fore and hind limb of various mammals reduced to the same absolute size, and showing in a very instructive manner the changes in the carpal and tarsal bones, and in the number and structure of the digits. From this summary of the contents of the different plates, an idea may be gained of the large amount of information to be derived from this Atlas, the production of which at a comparatively moderate price does great credit to the publishers. The drawings are executed in a very artistic style, and with the great advantage of the supervision and nomenclature added by Professor Huxley, they cannot fail to prove a great boon to the student in comparative anatomy. VI.-PETERS, Carus and GersTAECKER'S HANDBOOK OF ZOOLOGY. HANDBUCH DER ZOOLOGIE, Von W. C. H. Peters, Jul. Victor Carus, und C. E. Adolph Gerstaecker. Zweiter Band. Leipzig, Engelmann, 1863. 8vo. pp. 842. It is not quite a century since the twelfth edition of the Systema Naturæ of Linnæus made its appearance, and it would be neither uninteresting nor uninstructive if we could have a detailed history of the Manuals of Zoology that have been produced since that day. The fortunate zoologists who witnessed the publication of the Systema Naturæ, could take that immortal work as the guide of their first steps in the investigation of the mysteries of their science, and continue to walk by its light for the greater part of their course; but the very progress initiated by the publication of a good system soon did away with at least one portion of its value, and its importance as a "Species Animalium" was not of long duration. Within little more than twenty years after the appearance of Linné's 2 twelfth edition the gigantic compilation of Gmelin showed the world that Natural History, in its rapid progress, had already outgrown the limits of any single book, and that thereafter the elaboration of a general system of Nature, with descriptions of all the species, was to be regarded as an impossibility. Blumenbach's Manual is an example of an elementary systematic work, giving the general outline of the Linnæan classification; but within ten years of the publication of Gmelin's edition of the Systema Naturæ, Cuvier commenced the work of innovation by the production of his Tableau élémentaire, in which he indicated the division of the Animal Kingdom into four groups, a system afterwards fully developed by him in the two editions of his Règne Animale. In all these works, as also in Lamarck's Histoire Naturelle des Animaux sass Vertèbres, an effort was made to give the characters not only of the larger groups, but of the genera, with descriptions of illustrative species, and many of us can recollect a time when the works of Cuvier and Lamarck formed the chief standards to which all newly established generic groups were referred. That time, however, has long since passed away, and from the rapid progress of Zoology during the last thirty years, the number of genera has increased so greatly, that, at the present day, any attempt to include short characters of all the genera of animals within a single book of moderate compass, is almost as impossible as it would have been for Cuvier and Latreille to have described all the species known to them in the five volumes of their Règne Animale. Many of our writers of Manuals have, accordingly, abandoned the description of genera altogether, contenting themselves with carrying their classification as low as the family groups, and indicating, or briefly describing, typical examples of each family. Others, again, and amongst them are the authors of the Handbook now before us, have endeavoured to give a selection of genera, a course of which we cannot altogether approve,―as, although a certain number of types may, by this means, be ascertained by the student, it is a question whether a much greater amount of usefulness might not be attained by omitting these partial generic details, and by devoting the space thus gained to the fuller elaboration of the structure and life-history of the more prominent members of the larger groups. Thus, in the work now under consideration, the generalities upon the organisation, functions, &c., of the Classes and Orders are reduced within the smallest compass, whilst some of the most important questions of modern Zoology, such as those relating to the |