Supplement to "Nature" November 6, 1902. 



IX 



attitude to various general problems. It is, on the whole, 

 conservative. His embryological studies leave him more 

 than ever convinced of the unity of the Vertebrate phylum ; 

 the different modes of cleavage can be readily unified, but 

 there seems no doubt that the discoidal mode has arisen 

 several times independently ; the processes of gastrula- 

 tion (archi-, amphi- and disco-gastrula) can also be 

 unified as Haeckel maintained ; the two ways in whicli 

 the medullary canal arises are connected by transitions, 

 e.g. in Lepidosiren ; the neurenteric canal, which had 

 originally a nutritive significance, is another unifying 

 character ; and so on. It is more difficult to give a unified 

 account of the mesoderm, which may arise by pouching, 

 by splitting off, or by a proliferating process. " But,'' as 

 the author says, " one cannot ignore the fact that all 

 the modes of formation which occur in Vertebrates are 

 connected by transitional stages." Against the prevalent 

 view that the mode of origin by pouching, familiar 

 in Amphioxus, is primitive, Ziegler maintains that the 

 Vertebrate mesoderm arose originally as a proliferation 

 on each side of the blastopore-margin, and subse- 

 quently spread forwards along the dorsal wall of the 

 archenteron. In spite of some objections, which are 

 not ignored, the author remains a firm adherent to the 

 doctrine of the distinctiveness and "specificity" of the 

 germinal layers — " one of the most important results of 

 embryological research." In his concluding words, the 

 author expresses the mood of the whole book when he 

 says that embryology is luminous only in the light of the 

 evolution-idea. J. A. T. 



TWO BOOKS ON AMERICAN SPORT. 

 The Deer Family. By T. Roosevelt and Others. 



Pp. ix + 334 ; illustrated. 

 Salmon and Trout. By D. Sage and Others. Pp. x + 



417; illustrated. (New York: The Macmillan Co.; 



London : Macmillan and Co., Ltd., 1902.) Each 



volume S.r. 6d. net. 



BOTH these works belong to the "American Sports- 

 man's Library," of which Mr. C. Whitney is editor, 

 and both fully maintain the high standard of excellence 

 set by their predecessor in the same series, " Upland 

 Came Birds." President Roosevelt, whose name appears 

 first on the title-page of the volume on deer, is an excel- 

 lent type of the best class of naturalist sportsmen, and 

 of his three coadjutors Dr. D. G. Elliot, who writes on 

 caribou, is a zoologist of high reputation, while Mr. A. J. 

 Stone, who treats of the moose, is a famous Alaskan 

 explorer and field-naturalist. Mr. Roosevelt, who con- 

 tributes a thoughtful introduction to the volume, describes 

 the deer of the Rocky Mountains and Eastern America 

 as well as the prong-horn antelope ; while the deer of the 

 Pacific coast fall to the lot of Mr. T. S. Van Dyke. The 

 only disadvantage we see in this arrangement is that the 

 mule-deer is described twice over. 



In his introduction, Mr. Roosevelt refers to the different 

 views entertained as to the number of distinguishable 

 forms of American deer and their nomenclature, but sums 

 up by observing that there are only six wholly distinct 

 kinds, the moose, the caribou, the wapiti, the whitetail, 

 the mule-deer and the blacktail. With this philosophical 

 view we are thoroughly in accord, and if all zoologists 

 NO. 1723, VOL. 67] 



would but agree to regard these, and these only, as 

 species, the subject would be much simplified. It is 

 satisfactory to note that Dr. Elliot takes practically this 

 view in his chapter on the various local forms of caribou. 

 In consequence, apparently, of the divergent views 

 prevalent in regard to nomenclature, Mr. Roosevelt very 

 wisely avoids scientific names altogether, although such 

 names do appear on the valuable maps showing the 

 range of each species, which have been contributed to the 

 work by Dr. C. H. Merriam. 



The great decrease which has taken place of late years 

 in the numbers of American big game is deplored by Mr. 

 Roosevelt, who nevertheless urges that if proper game- 

 laws be enacted and adequately enforced and " sanc- 

 tuaries" established, most or all of the species may be 

 preserved for many years to come. The professional 

 skin and trophy hunter is the man who does most harm 

 to big game, and next to him the " big-bag" sportsman, 

 who receives a severe " slating " at the hand of the 

 President. 



Limitations of space forbid any detailed notice of the 

 text, and it must accordingly suffice to say that in the 

 case of each species attention is very fairly divided 

 between the natural history and the sporting aspects of 

 the subject ; in fact, the whole volume is just what a work 

 of this nature ought to be. The authors have been spe- 

 cially fortunate in their artists, among whom the name of 

 Mr. C. Rungius occupies the post of honour. Among 

 the numerous full-page illustrations in the volume, the 

 one that most takes our own fancy is that of the Colorado 

 mule-deer, or blacktail. It may be added that Dr. 

 Elliot (p. 268) authenticates, by reference to an old 

 sporting work, the statement (recently discredited by an 

 American writer) that caribou formerly crossed from 

 Newfoundland to the mainland on the ice. 



The second of the two volumes is written on somewhat 

 more technical lines than the first, the writers giving full 

 lists, with the scientific names, not only of the species, 

 but likewise of the subspecies of the salmon group. 

 The first section of the book, by the author whose name 

 is mentioned with the title, is exclusively devoted to the 

 true salmon, which is common to both sides of the 

 Atlantic. Unhappily, from want of due protection, this 

 noble fish has been practically exterminated from the 

 rivers of the U"nited States, and, in the author's opinion, 

 it would take ten years to fully restock them. On the 

 other hand, " the British Possessions in North America 

 undoubtedly afford the greatest field for the salmon 

 angler of the future in any part of the globe." As Mr. 

 Sage is a practical and observant fisherman of many 

 years' standing, his remarks on the vexed question whether 

 salmon feed while in fresh water are deserving of atten- 

 tion. His opinion is that they do, and his explanation of 

 the fact that they are so seldom caught, even in the sea, 

 with food in their stomachs is that they are in the habit 

 of disgorging when threatened by danger. Several in- 

 stances are cited of salmon seizing objects of consider- 

 able size with the apparent intention of swallowing them. 



The ugly though valuable Pacific salmon of the genus 

 Ogmorhinus, which often occur in such myriads in 

 Alaskan waters and afford almost the whole of the 

 world's supply of tinned salmon, are described by 

 Messrs. Townsend and Smith, by whom five species are 



