bones for the insertion of muscles; are the consequences of nutri. tive and formative excitation, transmitted by heredity." In this position Professor Raymond is in strict accord with the American school of evolutionists. He then goes on to say: "It is necessary to admit along with development by use, development by natural selection, and that for three reasons. First, there are innumerable adaptations—I cite only those known as mimetic coloration-which appear to be only explicable by natural selection, and not by use. Second, plants which are, in their way, as well adapted to their environment as animals, are of course incapable of activity. Thirdly, we need the doctrine of natural selection to explain the origin of the capacity for exercise itself. Unless we admit that which it is impossible to do from a scientific standpoint, that designed structures have a mechanical origin, it is necessary to conclude that in the struggle for existence, the victory has been secured by those living beings who in exercising their natural functions have increased, by chance ("par hasard") their capacity for these functions more than others, and that the beings thus favored have transmitted their fortunate gifts, to be still further developed by their descendants." In these three propositions, Professor Raymond still clings to the obscurities of the Darwinians, though Darwin himself is not responsible for them. To take up first the second and third of these propositions. Professor Raymond does not for the moment remember that movement (or use) is an attribute of all life in its simplest forms, and that the sessile types of life, both vegetable and animal, must, in view of the facts, be regarded as a condition of degeneration. It is scarcely to be doubted that the primordial types of vegetation were all free swimmers, and that their habit of building cellulose and starch, is responsible for their early-assumed stationary condition. Their protoplasm is still in motion in the limited confines of their walls of cellulose. The movements of primitive plants have doubtless modified their structure to the extent of their duration and scope, and probably laid slightly varied foundations on which automatic nutrition has built widely diverse results. We may attribute the origin of the forms of the vegetable kingdom to three kinds of motion which have acted in conjunction with the physical environment; first, their primordial free movements; second, the intracellular movements of protoplasm; third, the movements of insects, which have doubtless modified the structure of the floral organs. Of the forms thus produced, the fit have survived and the unfit have been lost, and that is what natural selection has had to do with it. The origin of mimetic coloration, like many other things, is yet unknown. An orthodox Darwinian attributes it to "natural selection," which turns out, on analysis, to be "hasard." The survival of useful coloration is no doubt the result of natural selection. But this cannot be confounded with the question of origin. On this point the Darwinian is on the same footing as the old time Creationist. The latter says God made the variations, and the Darwinian says that they came by chance. Between these positions science can perceive nothing to choose.-C. :0: RECENT LITERATURE. THE DEVELOPMENT OF AMPHIOXUS BY HATSCHEK.-The entire organic world does not contain a more interesting animal than the lancelet, Amphioxus or Branchiostoma, the lowest vertebrate, the link which, though far removed from either, indicates a common origin, or at least a remarkable structural similarity between the Vertebrata and the Ascidians or Tunicates. The literature upon this creature, extensive but incomplete, is now enriched by the present exhaustive memoir by one of the most careful and accurate of European biologists. In this memoir, which forms the greater portion of a late issue of the Arbeiten of the Zoological Institute of the University of Vienna, and is illustrated by nine large plates, carefully drawn and colored, the development of the lancelet is traced with the greatest minuteness from the ovum to the adult. The ovum of Amphioxus contains, between the germinal portion and the enclosing membrane a remarkably large water space, forming by far the greater portion of its bulk, and the cleavage is very near regular, the difference between the size of the cells separated by the first equatorial fissure being very small. The "blastula" stage with its large segmentation cavity, and the gradual formation of a "gastrula," are abundantly illustrated; two plates are devoted to the more advanced development, plainly showing the hollow structure and alternate position of the muscle-pla tes or myocommas, and three colored plates are filled with transverse sections. Until an advanced period of embryonic life, the digestive tract is continuous with a dorsal canal, which terminates at an opening upon the upper surface of the head. At a later period the vent is formed, connection between the digestive tract and the dorsal canal is cut off, the anterior opening closes, and the dorsal canal becomes the neural canal. The hollow form of the muscular segments is shared by the lancelet with the Selachians (sharks and rays), Cyclostomes (hags and lampreys) and Batrachia, and tends to prove their primary origin as diverticula from the digestive cavity. In the notochord vacuoles are developed, which become larger, Studien über Entwickelung der Amphioxus. Von B. HATSCHEK, pp. 88. 9 double Svo plates. Arbeiten aus Zool. Inst. Univ. Wien und der Zool. Station in Triest. Tom IV. TOL. XVI.-NO. IV. 21 obliterating the structure of the original notochordal cells, until finally the notochord consists of a series of clear spaces separated by hyaline partitions. These vacuoles are traceable also in tunicates, and in the teleosts or bony fishes. In conclusion, we have to say that Hatschek has given to the world a most valuable addition to its stock of embryological knowledge. TROUESSART'S CATALOGUE OF RECENT AND FOSSIL MAMMALS.— Catalogues of animal forms are as necessary to a student of zoology as are catalogues of books to the frequenters of a library, or directories to dwellers in cities. No zoologist can carry in his brain, ready at an instant's notice, the accepted name, synonymy, etc., of all the species included in the department he specially studies, and thus such works as Gray's Hand-List of Birds, and the present are great boons to him; they save him hard work, and leave him free to exercise his mind upon purely scientific work. Dr. Trouessart's catalogue, which has already progressed to the completion of the Primates and Rodentia promises to be to mammalogists what Gray's Hand-List is to ornithologists, with the added recommendation that it contains also all known species of fossil mammals, and will therefore prove equally useful to the palæontologist. The classification adopted is to a great extent that of modern authors with the addition of the orders proposed by Professor Cope, and is based upon the structure of the feet and teeth, except in the division of all mammalia into the universally accepted sub-classes Monodelphia (placental) and Didelphia (non-placental). The Prosimiæ (Lemurs) are separated as an order from the Simiæ; Cope's order Bunotheria, with four extinct sub-orders (Mesodonta, Creodonta, Tillodonta, Taniodonta), and one recent sub-order (Insectivora), is placed among the Secundates, or unguiculates; the Toxodonta are considered a sub-order of Rodentia, and the Zeuglodonta has the same rank among the Pinnipedia. The line of hoofed animals or Ternates is concluded by the Amblypoda, with two sub-orders, Dinocerata and Pantodonta; the porcine group is separated as a sub-order from the ruminants, and the order Sirenia is intercalated between the Edentata and the Cetacea. The last mentioned three orders form the group Homodonta, of equal rank with the Heterodonta, which includes the remaining monodelphian orders. The catalogue gives, besides genera, sub-genera, and species, the habitat, the synonymy, and all varieties on which species have been founded. When these varieties are merely local, or perhaps based on individual characters, they are marked with the 1 Catalogue des Mammifères Vivants et Fossiles. Par le DR. E. L. TROUESSART. June, 1878. letters a, b, c, etc., but these letters are doubled when the varieties have the weight of races or geographical species, while fossil species and genera are marked by the sign †. There are points in the classification adopted that may reasonably be objected to. The most important of these is the creation of the group Homodonta to include the sirenians, whales and edentates, orders not closely allied, and differing much in the structure of the teeth. The terms Secundates and Ternates are new, and are no improvement upon the older terms Unguiculata and Ungulata, the last of which should be understood to comprehend four orders, viz., Proboscidea, Artiodactyla, Perissodactyla, and Amblypoda. It is not possible to discover anatomical characters of sufficient importance to warrant the separation of the Bimana from the Simiæ, and it is probable that the Prosimiæ should be placed in the bunotherian series of sub-orders. This last probability is hinted at in the prospectus. BETTANY'S PRACTICAL BOTANY.-This useful little book should have been called First Lessons in the Practical Botany of the Flowering Plants, as it does not even mention the non-flowering plants. In the words of its author "its aim is to aid students in chools and colleges in the practical work of describing flowering plants." Some excellent suggestions are given under "How to Describe Plants." The "Cautions," too, are to the point. Under the successive topics, (1) Root system, (2) Stem and branch system, (3) Leaf system, (4) Inflorescence and floral receptacle, 5) Floral envelopes, (6) Stamens, (7) Pistil and ovules, (8) Fruit and seeds, short definitions and practical directions for the study specimens are given, which if followed step by step will enable pupil to observe accurately, and to record what he has seen in proper order and in plain language. Special directions are given in a later chapter for the study of the plants of the principal natural orders, which will doubtless prove useful to the student. the While we do not think it profitable to begin the study of botany with such complex organisms as the flowering plants, we nevertheless welcome this little volume because it can do good service in directing pupils to study plants rather than books on pants. The "laboratory method" is so fully carried out that the book can scarcely be studied by itself; the pupil must study the plant.-C. E. B. BALFOUR'S COMPARATIVE EMBRYOLOGY (SECOND NOTICE).-The chapter on the development of the birds is quite long, and the Embryology of the chick has been more thoroughly studied than that of any other animal. In the brief chapter on reptiles, the deFirst Lessons in Practical Botany, by G. T. Bettany, M.A., B.Sc., F. L.S. Macmilan & Co., London and New York, 18mo, 104 pp. velopment of the lizard is chiefly discussed. In the longer chapter on the mammals, several pages are devoted to the early stages in the development of man. The remaining two-thirds of the book are, in the present stage of embryological science, of much value to the student, as Professor Balfour here attempts the difficult task of stating the general conclusions derived from a survey of all authentic known facts regarding the embryology of animals in general. This is done successfully, the work well deserving the name of a comparative embryology. In chapter XI, we are presented with a comparative sketch of the mode of formation of the germinal layers, and the notochord, with a notice of the mode.of origin of the allantois and amnion. We notice here a little discrepancy in the author's statement regarding the allantoic bladder of the Amphibia, which leaves us somewhat in doubt as to the author's final opinion respecting its nature. On p. 108, the author states that the allantoic bladder of the frog "is probably homologous with the allantois of the higher Vertebrates;" on p. 587 he says that it "is homologous with the allantois of the amniotic Vetebrata," on p. 256, it is stated that there is "ample evidence" that the allantois "has taken its origin from a urinary bladder such as is found in Amphibia.” Chapter XII, observations on the ancestral forms of the Chordata, is mainly speculative. The author claims that it is clear from Amphioxus "that the ancestors of the Chordata were segmented, and that their mesoblast was divided into myotomes, which extended even into the region in front of the mouth. The mesoblast of the greater part of what is called the head in the Vertebrata proper was therefore segmented like that of the trunk." In the Amphioxus also the only internal skeleton present is the unsegmented notochord; a "fact which demonstrates that the skeleton is of comparatively little importance for the solution of a large number of fundamental questions." We have for some time inclined to the view that there was a general analogy between the head of an Arthropod and a Vertebrate, more intimate than generally stated, and Balfour's views on this point are of much interest. As to the differentiation of the Vertebrate head, he says on p. 260, "In the Chatopoda, the head is formed of a præoral lobe, and of the oral segment, while in Arthropods a somewhat variable number of segments are added behind to this primitive head, and form with it what may be called a secondary compound head. It is fairly clear that the section of the trunk, which, in Amphioxus, is perforated by the visceral clefts, has become the head in the Vertebrates proper, so that the latter forms are provided with a secondary head like that of Arthropods." Hence Balfour considers that the part of the head containing the fore-brain is probably "the equivalent of the |