196 



NATURE 



[December 15, 1910 



If we consider the work done, the number of first- 

 class investigations, and the importance of the deduc- 

 tions made from them, we have no reason to be 

 ashamed of our country's contribution to the general 

 advance. We can be proud that so many students 

 have proved their worth in the Cavendish and left it 

 to fill important positions elsewhere, proud, too, that 

 students from abroad have so freely acknowledged 

 their debt to its spirit of enthusiasm and generous 

 comradeship in research. It is true that the book 

 leads us to consider the general question of physical 

 research in England, and that we then find conditions 

 which are not completely satisfactory. We have still 

 to fight for the recognition of the value of such re- 

 search, and we must in some way improve on the 

 disjointed nature of the career of the research student. 

 Too often his only reward is a teacher's position in 

 which he finds difficulty in exercising the powers he 

 has educated. But we cannot enter on the considera- 

 tion of such questions now ; we are only concerned 

 with a book which fulfils admirably the purpose for 

 which it was written. 



A NEW BOOK ON REPTILES. 

 Reptiles of the World. Tortoises and Turtles, Croco- 

 dilians, Lizards, and Snakes of the Eastern and 

 Western Hemispheres. By R. L. Ditmars. Pp. 

 xix + 373 + 87 plates. (London: Sir Isaac Pitman 

 and Sons, Ltd., 1910.) Price 20s. net. 



PRIMARILY intended as a general survey of the 

 reptiles of the world treated in a popular 

 manner, the handsome volume which has just ap- 

 peared simultaneously in this country and in America, 

 will prove of special value to all who keep these 

 animals in captivity. The name of Mr. Ditmars is 

 a guarantee of accuracy and originality in the treat- 

 ment of a subject in which he excels over all others. 

 The success with which he has managed for some years 

 the largest collection of living reptiles in existence, 

 viz., that in the New York Zoological Park, is well 

 known. From early boyhood his enthusiasm for rep- 

 tiles, especially snakes, has led him to study the 

 habits of these reptiles, so repulsive to many, even 

 among educated people, and his house has always 

 been the headquarters of an extensive collection of 

 snakes, large and small, innocuous and venomous. 



The information he gives us is therefore thoroughly 

 trustworthy, unlike what we find in so many so- 

 called popular works, and we strongly recommend 

 this book to amateurs who keep reptiles in captivity, 

 as well as to those whose duty it is to look after them 

 in public menageries. 



The American species, of course, receive the lion's 

 share in a treatise emanating from America, and in 

 a publisher's note to this English edition the reader 

 is asked to bear in mind that the species referred to 

 by the author as musk turtles, mud turtles, pond 

 turtles, box turtles, &c., are known in this country as 

 tortoises, the term turtle being restricted to the marine, 

 and sometimes a few of the larger river species. The 

 reviewer would express the regret that the term Terra- 

 pin, used for some of the fresh- or brackish- water 

 tortoises in America, has not been made to include 

 NO. 2146, V^OL. 85] 



these intermediate forms, which are neither true tor- 

 toises nor turtles. Further, the name sand lizard, 

 applied to Acanthodactyliis boskianus (p. 38) is 

 misleading, as by sand lizard every English reader 

 would understand our Lacerta agilis, which has always 

 been known under that name. As is to be expected 

 from an author who is not exactly a systematist — 

 some may say all the better for the treatment of the 

 subject in a popular style, the information as to the 

 relationships and distribution of the animals dealt 

 with, and the number of species in each genus, is not 

 always quite up to date. Thus we notice that among 

 the Chelonians the Carettochelydidae are still included 

 among the Pleurodirans, to which they were tenta- 

 tively assigned before the skeleton was known, 

 although it is now established that they belong to the 

 Cryptodirans, in the neighbourhood of the Triony- 

 chidae. The common snapping turtle is said to extend 

 southward to Ecuador, whence it was first reported 

 by the late Prof. Peters ; but the reviewer was able to 

 show, many years ago, that the snapping turtle of 

 Ecuador is a distinct species, identical with the Central 

 American Chelydra rossignoni. No allusion is made 

 to the allied genus discovered a short time ago in 

 New Guinea. 



On the whole the author has adhered to the classifi- 

 cation and nomenclature used in the British Museum 

 catalogues (1885-96), but he has departed from the 

 latter in the case of many North American types, 

 which causes some confusion and a lack of harmony 

 in the systematic treatment of the subject. 



These are, however, very trivial defects. The great 

 value of the work lie's, as we have said, in the matter 

 relating to the habits of the reptiles, both wild and 

 in captivity, a subject on which the author is facile 

 princeps. 



The varied contrivances by which reptiles secure 

 their food, produce and rear their young, harmonise 

 with their surroundings, &c., are fully dealt with, and 

 in a thoroughly original manner. The size to which 

 the largest crocodiles and snakes grow is also dis- 

 cussed, and only trustworthy records are adduced. 

 The largest crocodile measures 30 feet, so does the 

 largest python, the anaconda rather more than 25, the 

 Boa constrictor only 11; but it must be borne in mind 

 that the name Boa constrictor is often applied to 

 pythons in menageries and by colonists in Africa. 



On the subject of snakes swallowing their young, 

 it is important to have the opinion of an observer of 

 such wide experience as Mr. Ditmars. "The storyj 

 of the female snake swallowing her young in time o^ 

 danger," he says, "is purely fallacious. It has origin- 

 ated from observations of cannibal species making 

 meal of young reptiles " (p. 203). Apropos of cannibalj 

 species, we wish to direct attention to the important 

 experiments made on the king snake {Coronella or 

 Ophibolus getulus) of North America, a harmless 

 species, w^hich is apparently immune to the venom o^ 

 such deadly pit-vipers as the rattlesnake, the copper-i 

 head, the mocassin, and the South American Lachesis,! 

 whilst it usually dies within an hour if injected with* 

 the poison of the old-world cobras. 



Mr. Ditmars's observations and experiments on 

 chameleons and other lizards with changing hues have 



