274 



KNOWLEDGE 



[Deoeubbr 2, 1896. 



batched much resemble the parent, and during growth 

 undergo a series of moults like spiders, scorpions, and in 

 fact all Arthropoda. But the process of growth seems to 

 be a slow one. According to Dr. Mars, bis young specimen, 

 above referred to, grew less than an inch m two years. 

 The moulting is effected as in scorpions and spiders by 

 the splitting of the skin along the sides of the cephalo- 

 thorax, beneath the carapace. Mr. Gates tells us that the 

 sexes grow up exactly alike until the final moult. 13ut the 

 male emerges from his last skin a very different looking 

 animal, with longer and stronger nippers, and thinner 

 body. 



Like many other harmless animals, the whip-scorpions 

 have been accredited with the possession of poison glands, 

 and in America there are even stories to the effect that 

 horses have been known to die from the effects of their 

 sting. They may, however, be handled with perfect 

 impunity, and dissection fails to reveal the existence of 

 poison glands. They have, nevertheless, a remarkable 

 means of defence in a pair of stink glands which open 

 upon the last segment of the body at the root of the tail. 

 These glands discharge a liquid, the odour of which is 

 said to resemble acetic acid or aromatic vinegar, and is 

 so powerful, ]Mr. Gates tells us, that it has frequently 

 betrayed to him the whereabouts of the animal, and, 

 according to Latreille, has earned for these creatures the 

 title linaifpieis from the French settlers in Martinique. 

 There cannot be much doubt that the irangency of this 

 fluid renders the whip-scorpions distasteful to such enemies 

 as insects and birds that would otherwise prey upon 

 them. But upon an occasion when some drops of it 

 were by chance discharged into Mr. Gates's eye, no 

 harmful results ensued. 



Another curious organ possessed by most genera of this 

 family may be here mentioned. This is the pair of clear 

 yellow spots found on the last segment of the abdomen. 

 The function of these is at present unknown, but it has 

 been suggested by Dr. Hansen that they may be luminous 

 organs like those to be seen on the fireily. But so far as 

 is at present known, this supposition has no foundation 

 in fact. 



Notices of iSoolts. 



— • — 



Studies in the Erolution of Animals. By E. Bonavia, M.D. 

 Pp. 362. (Constable it Co.) It seems to us that Dr. Bonavia 

 gives himself away in the first paragraph of the preface to 

 this work, for therein he says : " Having completed the 

 Flora of the Assyrian Monuments ami its Outcomes, I was 

 looking about for something to take up next as a subject of 

 study. In the furriers' windows I was attracted by the 

 leopard and tiger skins, which by degrees became objects of 

 mteresting study and speculation." This candid confession 

 startles those who are old-fashioned enough to think that 

 an author's first qualification should be a wide and deep 

 knowledge of his subject. The subject which Dr. Bonavia 

 happened to take up is the external coloration of mammals. 

 To begin with, he discusses the characters of the spots and 

 stripes on a number of mammals, and comes to the con- 

 clusion that, in the case of tigers, the stripes were derived 

 from spots or rosettes. Following up this notion, the 

 author derives the stripes of the zebra from the spotting of 

 dappled horses ; according to which view all horses and 

 asses and zebras were originally spotted, or have descended 

 from ancestors having spots not unlike those of the jaguar. 

 These points having been settled to the author's satis- 

 faction, the origin of the rosettes or spots themselves 

 is tackled, and the astounding conclusion is arrived at 

 that they represent the vestiges of bone -plate rosettes on 



a glyptodontoid type of mammal ; in other words. Dr. 

 Bonavia believes that the jaguar and other members of 

 the cat tribe have descended from some extinct ancestor 

 with a glyptodontoid carapace, and as this ancestor lost 

 its bone-rosettes, it left behind a pattern which we see 

 preserved in the spot-rosettes of the jaguar. The same 

 theory is applied to account for the markings of horses 

 and other mammals. The confidence with which Dr. 

 Bonavia builds up such a stupendous superstructure of 

 theory upon a slender basis of fact is simply prodigious ; 

 and how he is able to shut his eyes to the anatomical and 

 zoological evidence which controverts it passes our com- 

 prehension. Many other far-fetched conclusions are arrived 

 at in the book, the only redeeming feature of which is the 

 remarkably fine illustrations. It is a pity that these 

 pictorial embellishments should be used to prop up such 

 wildly- speculative theories. 



Practical Proofs of Cliemical Laws. By Yaughan 

 Cornish, M.Sc. (Longmans.) We have read this little 

 book with great pleasure, as the author has shown in it 

 that he is not only filled with the spirit of a true man of 

 science, but is also fully acquainted with the difficulties 

 which attend the imparting of that knowledge to others. 

 His exercises are carefully chosen, and as they are the actual 

 details of his own class experiments, there should be no 

 difficulty in their adoption by other teachers. We hope 

 that the time is not far distant when test-tubing will cease 

 to be designated chemistry in our public and secondary 

 schools, and that text-books of this practical description 

 will be used by teachers, so that the laws and foundations 

 of the science will be taught, and thus aid in sorting out 

 from the common herd those who are naturally gifted in 

 the scientific habit, and enable them to be selected by 

 their masters for further training and development. 



The Natural Ilistonj of Aquatic Insects. By Prof. L. C. 

 Miall, F.R.S. Pp. "805. (Macmillan.) Signs are not 

 wanting of a reaction against that method of studying 

 zoology which confines the observations to the laboratory, 

 and in favour of those broader lines of study foUowed by 

 the great naturalists of the seventeenth and eighteenth 

 centuries. England is the home of observers who take a 

 deUght in investigating the structure and habits of animals, 

 though their observations are not always properly appre- 

 ciated by systematic zoologists. Prof. MiaU's attractive 

 volume will, we are glad to say, induce many to join the 

 ranks of the old type of naturalists, and will help to 

 systematize the observations of those who are already 

 zealous, albeit aimless, students of the wonderful workings 

 of nature. Written in a style easily understood, and by 

 one who is able to impart sound information, the book will 

 undoubtedly take a permanent place among works on 

 natural history. The illustrations, many of which are 

 from new drawiags by Mr. A. Pi. Hammond, are like the 

 text — good and true. We know of no better guide to the 

 study of aquatic insects in a practical way than is aft'orded 

 by this book, and there are few books which tend to brmg 

 the reader into closer contact with nature. 



Petrohjijij for Students. By Alfred Harker, M.A., F.G.S. 

 (Cambridge University Press.) This introduction to the 

 microscopic study of rooks in thin slices belongs to the 

 carefully-prepared and well-produced series of Cambridge 

 Natural Science JIauuals. With the exception of Prof. 

 Cole's "Aids in Practical Geology," we know of no English 

 text-book on the microscopical characteristics of minerals 

 and rocks more suitable for beginners ; and as the book 

 before us deals entirely with petrographioal matters, it is 

 even more acceptable to the specialized student than Prof. 

 Cole's volume, which takes a larger view. The classification 

 of massive igneous rocks adopted by Mr. Harker is into 



