numerous illustrations with which it is embellished make almost sufficient amends for the shortcomings in the text, which may be improved in a future edition. A Monograph of the Land and Freshwater Mollusca of the British Isles. By J. W. TAYLOR. With the assistance of W. D. ROEBUCK, C. ASHFORD, and others. Part II., pp. 65-128. With coloured frontispiece and numerous illustrations. Leeds: Taylor Brothers, Sovereign Street. 1895. THE first part of this new work on British Mollusca was reviewed in the number for February last (pp. 79-80), when we took occasion to commend the thorough mode of treatment adopted by the author, and the excellence of the illustrations, which are numerous. In Part II., now before us, we are pleased to see this high standard of merit maintained. The author, continuing his introductory observations, deals in this number with the subjects of variation in form and size, colour and markings, monstrosities, and auxiliary and protective organs. Size is influenced not only by the obvious causes of the abundance or scarcity of suitable and nutritious food, but is also in a great degree dependent upon temperature and other circumstances. The researches of Semper on the phenomena of growth upon which size is dependent, have shown that in Limnæa stagnalis, for example, the size attained by the shell is capable of correlation with the temperature and amount of the inhabited water, as assimilation and growth equally ceased if the degree of warmth exceeded 90° F., or fell below 53° F.; the fullest vigour being enjoyed, and the largest size attained when the temperature ranged between 68° F. and 77° F. The results of these researches are of great interest, and are more or less applicable to other species, as demonstrating some of the conditions governing growth-and therefore size-in Mollusca generally; and clearly establish that the volume or amount of water allowed to each mollusc is so decisive in its effect upon growth, that in the space of six days, the difference in the size of the shells of those in a large and those in a small body of water becomes apparent; the smaller the amount of water per indi vidual the smaller the shell, and vice versa. The colouring of the Mollusca, according to Mr. Taylor, seems largely dependent upon the action of light. The more exposed surface of spiral shells, and the posterior end of burrowing bivalves, are usually more richly coloured or ornamented than the less exposed or buried portions, and colouring generally is probably of great biological importance. It is also, as in other groups, most pronounced in brilliancy and variety in the warmer regions of the globe, and becomes gradually reduced in diversity and beauty as the poles are approached. These facts led Dr. Fischer to propose for the Mollusca three zones of colouration corresponding with the thermal ones. An examination of several thousand specimens of Helix nemoralis from the sand-hills at Spurn Point, Yorkshire (one of the driest spots in the kingdom), showed that scarcely a dozen of them exhibited evenly developed and strongly marked banding; the bands, when present, were all more or less broken up and disconnected. In this section of the general subject, Mr. Taylor gives a score of excellent figures to illustrate his remarks. No less interesting are his observations on monstrosities. All molluscs with spiral shells are liable to a reversal in the direction of their convolution; and bivalves, and even slugs, says Mr. Taylor, are affected in an analogous way. The causes of this reversal of the normal arrangement are, however, not at all known or understood. M. Bourguignat has hazarded the suggestion that it may be caused by electrical conditions, the electric current flowing in the opposite direction to the embryonal rotation, the essential conditions being a metalliferous soil, moist weather to influence the latent electricity of the metallic substances, and the conjunction of the atmospheric and terrestrial electricity, as by thunder at the period of first manifestation of vitality by the embryo. Prof. Carus, also, considers that the direction of the coiling of the shell and animal may possibly be determined by the direction of the embryonal rotation. These and other kindred topics are fully discussed and elucidated by Mr. Taylor, who brings a wide knowledge of the literature of the subject to bear upon his own researches, and those of his colleagues. His remarks upon Auxiliary and Protective Organs are especially interesting, but to discuss them here is not possible in the limited space at our disposal. We must be content to congratulate the author upon the progress of his work, and recommend it to our readers as one which promises to be a standard book of reference on the subject of which it treats. A Handbook of British Lepidoptera. By EDWARD MEYRICK. 8vo. pp. 843. With text cuts, showing the Neuration of Typical Species. London: Macmillan & Co. 1895. In a well written Introduction of twenty pages, Mr. Meyrick foreshadows the plan and scope of his work, which may be commended for its originality and comprehensiveness. The preparation of more than 800 closely-printed pages indicates a vast expenditure of thought and labour, which it is to be hoped will not have been bestowed in vain. Entomology is a subject which seems to increase annually in popularity, and of late years has been rendered more than ever fascinating through the efforts of workers like Miss Ormerod, and some of the American State Entomologists, who have given us such interesting life-histories of many of the insects which are injurious to agriculture. This, however, is not Mr. Meyrick's aim in the present volume, which is an elementary guide to the classification of the Lepidoptera, designed to enable collectors to identify specimens with accuracy, and acquire such general knowledge of structure and affinities as ought to be possessed by every student of Entomology before proceeding to more special investigations. The chief merit of this work, so it seems to us, lies in the fact that the structural characters have in every instance been described from the author's own observations. The importance of this becomes apparent when we remember that Stainton's 'Manual of British Butterflies and Moths,' so long regarded as a leading text-book, is sadly deficient in this respect, since it affords no satisfactory information on structural distinctions (except in the Tineina, which that author had specially studied), the nearly valueless characters assigned to the other groups being simply copied from other writers, and mainly from the pseudo-scientific work of Guenée. Mr. Meyrick's 'Handbook,' on a sounder basis than the 'Manual,' bids fair to supersede it. From it a species may be quickly identified by means of the Analytical Keys which form a special feature of the work, and following the "Introduction" is a useful "Glossary," and a "List of Abbreviations of Author's names." Buckram gilt, price 218. British Birds' Nests: How, Where, and When to Find and Identify them. By R. KEARTON, Author of "Birds' Nests, Eggs, and Egg Collecting." With an Introduction by Dr. BOWDLER SHARPE. Containing nearly 130 Illustrations of Nests, Eggs, Young, etc., in their natural situations and surroundings, from Photographs by C. KEARTON. Medium 8vo, 384 pages. The distinguishing features of the literary portion of this work are that it is arranged in alphabetical order, and all its information so classified as to admit of rapid and easy reference. The parent birds; situation, locality, materials, and chief characteristics of the nest; the number, size, and colouration of the eggs; breeding months; migratory habits; call, alarm, or song notes; local names; and behaviour at and on leaving the nest, are all carefully described for purposes of discovery and identification of the nest and eggs of each species. The great feature of the book, however, lies in the unique character of its Illustrations, every one of which has been made from a photograph taken in situ. These represent the nests, eggs, young, and in some cases the old birds too, of about III species, and include a very fine picture of the nest, young ones, and prey of the Golden Eagle. Many of the photographs have been procured at great personal danger and trouble, and the author will give a short account of the difficulties and adventures encountered in obtaining them. No less an authority than Dr. Bowdler Sharpe, of the British Museum of Natural History. South Kensington, says in his introduction to the book that in point of illustration it is as era-marking as the celebrated works of Gould and Booth. CASSELL & COMPANY, LIMITED, London, Paris & Melbourne. |