280 



KNOWLEDGE. 



[December, 1901. 



a mastodon is a large elejiliant, and still more so that its tet-tli 

 are always tubercuUite instead of ridged. ^Moreover, like many 

 morphological ivriters, the authors are not sound on the subject 

 of nomenclature, otherwise they would not retain, albeit in 

 a half-heartt'd kind of way, the title Hyrax for the dassies. 



These and other blemishes of a like nature, although un- 

 fortunate, do not, however, in any way detract from the value 

 of the work, which may shortly be described as excellently adapted 

 to supply the needs of the class of readers for whom it is 

 intended, 



" A Tbeatise on ZooLor.T ; Part IV. The Pl.^tthelmia, 

 Me.sozoa, and Nemektini." By W. B. Benham. (A. & C. Black.) 

 Illustrated. 15s. net. — Contrasted with the work just noticed, 

 the volume before us presents a striking instance of the diversity 

 of view still prevalent among zoologists on many point.s. In 

 the first place the name Platyhelmia is adopted instead of 

 Platyhelminthes for the Flat-worms, and both this group and 

 the Nemertines are definitely included in the Coelomata (or Ccelo- 

 mociX'la, as the editor prefers to call this large assemblage), 

 whereas, as we have seen, the authors of the foregoing work 

 .state that there is no justification for such inclusion. Nor does 

 the want of agreement stop here, the Rotifera in the present work 

 being far removed from the neighbourhoixl of the Flat-worms 

 and Nemertines. As it is not our purpose to discuss which 

 of the two views has the greater probability of right on its 

 side, it will suffice to call attention to the existence of such 

 diversity of opinion. 



In the present volume the subject is treated with the .same 

 accuracy and fulness of detail as is apparent in its jiredecessors ; 

 and the beautiful illustrations afford the student every assistance 

 possible towards a right understanding of the te.xt. In tlie 

 author's opinion, the Planarians, together with their offshoots 

 the Flukes and the Tape-worms, collectively constituting the 

 Platyhelmia, are regarded as standing at or near the base of 

 the Ccelomoccela ; while the Nemertine worms form a distinct 

 " phylum," from which it is considered probable the Annelids 

 have originated. The ideal ancestral type is taken as the best 

 means of illustrating the structure and affinities of the Flat- 

 worms ; whereas in the Nemertines it is considered preferable 

 to take a " central type " as the basis of description. 



The Tapeworms have a special, although unpleasant interest, 

 on account of the marvellous nature of their transformations, 

 and tlie connection of several of them with the human body. 

 In a brief historical sketch the author states that these creatures 

 were probably known to Moses, and were certainly familiar to 

 Aristotle, who distinguished betiween eAf/ii«e! irAaie^ai, or Tape- 

 worms attached to the walls of the intestine, and sTpoyyvAai, or 

 free Nematodes. The gradual acquisition of our knowledge of 

 the migrations and transmutations of these organisms is then 

 referred to, after which we have an excellent series of descrijitions 

 of the life-history of the different members of the group. 



So far as we can judge, the pre.sent volume is in every way 

 worthy of the great work of which it constitutes an important 

 and interesting section. 



"Bird Watching." By Edmund Selous. ' Haddon Hall 

 Library. (Dent.) Illustrated. — In the preface to this volume 

 the author apologises for so many shortcomings that to avoid 

 repetition there seems little else for the reviewer to do but to 

 praise. Nevertheless, although the subject matter of the book 

 is extremely good and valuable, in our opinion Mr. Selous has 

 practically thrown his opportunities away, and has produced 

 a work written in so prolix a style that to read it is a tedious 

 and almost annoying task. The "bulk of the book is a mass of 

 minute and undoubtedly accurate observations of the habits of 

 birds, forming a record of almost every action of the birds watched 

 at every hour of the day. Intersper.sed amongst these voluminous 

 not«s are excursions into theory and specnlatiou whicli we need 

 only say tlie author would have been well advised to omit. It 

 is a great pity that the author's powers of observation, or "watch- 

 ing," to use the word he prefers, which have been well used, 

 should have been lost to the public by a want of a little careful 

 editing. Had Jlr. Selous digested his note-books instead of printing 

 them in full, and had he given us a narrative of the results of 

 his digestion, the out^;ome would have been, we feel sure, both 

 pleasing and profit*ble. 



As it is we can only recommend the volume to ornithologists 

 as a somewhat clumsy book of reference, but ornithologists .should 

 certainly possess it, since firsthand information is always of 

 value however presented. We h;ul no wish to further criticise 

 Mr. Selous, but we cannot refr.iin from an expression of regret 

 at his ignorant sneer at colk^tors, to whom if he reflected but 

 for a moment he would realise tliat every naturalist owes much. 



Mr. Smit has illustrated tlie book very nicely, but why .so 

 good a bird-artist should perpetuate with his pencil in a book of 

 facts such an ancient fable as tliat of the stork transporting small 

 birds over the sea passes compreheDsion, Mr. Smit has drawn 



tlie stork with its wings raised, and five thrushes comfortably 

 sitting in the hollow of its back. How would the artist have the 

 trick performed when the stork's wings are making the down- 

 stroke ? 



" The Evolution of Sex." By Prof. Patrick Geddes and J. 

 Arthur Thomson. Revised Edition. (Walter Scott.) 6s. Illus- 

 trated. — This is a revised edition of a book which appeared 

 twelve years ago and has attracted the attention of many students 

 of biology, both on account of its exceptional originality, and, 

 if we may say so, because of the bearing of matters with which 

 it deals upon the cytological work of recent years. The funda- 

 mental cause which has led to the differentiation of sex is con- 

 sidered bv the authors to be difference of metabolism. All 

 changes which occur in the body can be referred to the metabolism 

 of protoplasm, and the ratio of the constructive to destructive 

 processes is variable, the former preponderating in females and 

 the latter in males. In most cases females are relatively more 

 passive than males, that is, they do not spend so large a pro- 

 portion of energy in active habits. Moreover, observations and 

 experiments show that conditions favourable to constructive pro- 

 cesse.s — anabolic conditions as they are called — tend to produce 

 femaleness of offspring, while the opposite, or katabolic, conditions 

 tend to produce males. Nutrition is thus an important factor 

 in determining sex, but there are many other factors, such as 

 temperature, age of parents, etc., and their influence is slowly 

 being understood. This is a general statement of the thesis 

 which Professors Geddes and Thomson seek to establish. As 

 can easily be understood, the subject is a very intricate one, 

 as well as of deep interest, because it goes to the root of the 

 explanation of biological differences. To our thinking, however, 

 a large part of the book is not directly connected with the 

 evolution of sex, and a sub-title expressing the fact that the 

 development and inheritance of the cell and of the individual 

 might be added with advantage. A misprint occurs on p. 58, 

 where females are said to be relatively more katabolic than 

 males, whereas the reverse is the case. 



" Our Countrt's Shells and how to know them : A Guide 

 t.) the British Mollu.sca." By W. J. Gordon. 33 plates. 

 (Simpkin.) 6s. — The first part of the title very accurately 

 indicates the scope of the book, which will be found invaluable 

 to those who are making collections of the shells of the native 

 mollusca and desire to be .able to classify and name them. The 

 schemes of identification are very well arranged, and the descrip- 

 tions of species supply all the necessary information. The 

 illustrations, by A. Lambert, are excellent. The thirty-three 

 coloured plates give representations of all the British species 

 having shells ; and the black-and-white diagrams fulfil their pur- 

 pose no less satisfactorily. The style of the letterpress is bright 

 and interesting, but the author often uses undefined technical 

 terms which will embarrass the beginner. The glossary at the 

 end is a necessary feature. A very scrappy account only is given 

 of the physiology and internal anatomy "of the mollusca. The 

 book would have been materially improved by a preliminary 

 chapter giving exact instructions for dissecting two or three 

 ccmmon tyi>es, with simple eixplanations of the duties of the 

 various organs. _ We are glad to notice the table of - synonvms 

 on pp. 63 and '64. 



"Knowledge Diary and Scientific Handbook for 1902," 

 the second year of issue, is now published. In the Diary portion 

 of the work a whole page is provided for the observations of 

 each day, while there are separate pages for monthly notes, 

 irdexing, .and other objects. The following features of tlie hand- 

 book portion .should prove esjiecially useful to workers in 

 astronomy : —The paths of the planets for the year illustrated 

 with maps, astronomical phenomena of the year, monthly star 

 maps showing the positions of the constellations and principal 

 st.ars, how to use an equatorial telescope, the observation of 

 comets and meteors, and numerous astronomical tables. Other sciences 

 are dealt with by articles on Field Botanv, by Mr. R. Lloyd 

 Praeger, The Microscope and its Uses, bv Mr. M. I. Cross, 

 and Meteorology in Theory and Practice, by "Mr. Arthur H. Bell;" 

 while there is much other useful and interesting information of 

 a more general character. The price is three shillings. 



BOOKS RECEIVED. 



Anticipations of the Keacfion of Mechanical and Scientific 

 Progress upon Human Life and Thought. By H. G. Wells. (Chap- 

 man * Hall ) 79, 6d. 



Thought Power : Its Control and Culture. By Annie Besant. 

 (Theosopliical Publishing Society.) Is. 6d. net, 



Peeord of the Progress of the Zoological Soeie/g of London during 

 the Nineteenth Centuri/. (Zoological Society.) 



Photography for Naturalists. By Douglas English. (Iliffe.) 

 Illustrated. 59. net. 



Eoads : Their Construction and Maintenance. By Allan Greenwell, 

 A M.I.CB,, T.G.s,, and J. V. Ehiden, b.sc, f,o.s. (Builder Office.) Ss! 



