150 



SCIENCE 



[N. S. Vol. XXXVII. No. 943 



down. The lettering on the coracoid process, 

 Fig. 108, is incorrect. The olecranon process 

 is described on page 120 as extended beyond 

 the elbow joint to the attachment of the ex- 

 tensor muscles of the lower limb. The letter- 

 ing of the pancreatic duct in Fig. 242 does not 

 correspond with that of the legend. 



Kingsley's book lends itself for comparison 

 most readily with Wiedersheim's " Compara- 

 tive Anatomy of Vertebrates," especially with 

 the English edition edited by W. N. Parker. 

 The general field covered is similar, although 

 there are about one hundred more pages in 

 Wiedersheim. Wiedersheim has the advan- 

 tage of having been extensively used and re- 

 vised since the first edition in 1882, so that 

 the weaker parts have been gradually strength- 

 ened and the cruder errors eliminated. On the 

 other hand, a text-book revised from year to 

 year over so long a period inay display many 

 points of view less satisfactorily than a text- 

 book newly written. The relatively greater 

 attention given by Kingsley to histology and 

 embryology is a distinct advantage and might 

 be satisfactorily carried out further. On the 

 other hand, both illustrations and text de- 

 scriptions are, in many phases, clearer in 

 "Wiedersheim's than in Kingsley's text-book. 

 The bibliography given in Wiedersheim is far 

 more extensive, but, on the other hand, that 

 given in Kingsley is, on the whole, well se- 

 lected, and, possibly, for beginning students, 

 by being less extensive may be more useful. 

 C. E. Bardeen 



The University of Wisconsin 



The Growth of Groups in, the Animal King- 

 dom. By E. E. Lloyd, M.B., D.Sc. Lon- 

 don, Longmans, Green and Co. 1912. Pp. 

 185, with two colored plates. Price $1.75 

 net. 



" The aim of this small book is to lessen the 

 belief in natural selection as a creative 

 agency." " The word group appears in the 

 title of this work and will be found through- 

 out the text. It is used in place of the more 

 usual terms species, sub-species and variety." 

 " A group is a number of individuals (more 

 than one), each possessing some particular 



character or characters which are chosen arbi- 

 trarily as the distinguishing marks of that 

 group." " From a practical point of view 

 species ai'e those groups which have been de- 

 scribed as such." 



Although the idea expressed in the last 

 quoted sentence is by no means novel, it is 

 interesting as illustrative of a change which 

 seems to be coming over biology. Many will 

 still dispute both the author's and the re- 

 viewer's statements. However, it is indis- 

 putable that not only is the " method of the 

 origin of species an open question," but it is 

 more than ever a question as to what a species 

 is if it be more than a mere convention. It is 

 curious that so many well-informed tax- 

 onomists accept evolution as a principle, but 

 stick to the independent creation of species in 

 practise. The " splitters " are unconsciously 

 breaking down this practise, for species are 

 being based on fewer and less important char- 

 acters than ever. The process is a reductio 

 ad ahsurdum and can not help but end in the 

 definition of species just given. The author 

 seems justified in saying : " If it is true that 

 our conception of a species has changed it is 

 necessary to modify our opinion as to the 

 origin of a species. Some of those who are 

 interested in the origin of species do not know 

 how small are the differential gaps which 

 separate our modern species." 



About half of the book is devoted to an 

 account of the different sorts of rats found 

 among about 100,000 killed during the work 

 against the plague in India. Some of these 

 have already received names differentiating 

 them from Mus rattus. Other have not. As 

 a contribution to our knowledge of the amount 

 of readily appreciable variation in a feral 

 " group," this work is valuable. It is the only 

 important original thing the book contains 

 and is followed by a lengthy resume of some 

 of Tower's work upon Leptinotarsa. Unfor- 

 tunately the author did not subject the rat 

 " mutants " to experimental tests, nor does he 

 refer to the breeding work already done with 

 rats. The facts collected are believed to be 

 in harmony with that part of the mutation 

 theory which asserts that the attributes of 



