February io, 1910J 



NATURE 



445 



as an ornamental stone. There is a somewhat exceptional 

 niiiigling of sound geology and mining applications in this 

 compact report. The Survey shows a keen interest in 

 palaeontology in its Records, vol. viii., part iv. (1909, 

 price -s.'^d.). Mr. R. Etheridge, among pther contribu- 

 tions by him, describes a large tubular organism from 

 Gotlandian strata, allied to the Carboniferous Mitchel- 

 <!eanla. Dr. \. S. Woodward adds to our knowledge of 

 the labyrinthodont Bothriceps. Mr. G. W. Card continues 

 his painstaking determinations of the minerals of the 

 State, and the analyst, Mr. J. Mingaye, supplies details of 

 importance to all chemists as to the modes of separation 

 of thoria from monazite tp. 276). 



Mr. \V. E. Cameron lias written for the Queensland 

 Geological Survey a second report on the Etheridge Gold- 

 field (Brisbane, 1909), where the ores occur in reefs in 

 granite, or associated, like those of the Drake Field in 

 New South Wales, with basic dykes, which here penetrate 

 schists. The Survey has also issued a third edition of a 

 very useful geological and mining map of Queensland, on 

 the scale of \ inch to forty miles. 



In Bulletin No. 6 of the New Zealand Geological Survey 

 (iqoS, price 2s. 6(i.) Mr. P. G. Morgan describes the 

 southern part of North Westland, on the western coast 

 of tlie South Island. The author feels strongly that high 

 ground existed in the oceanic area to the west down to 

 the commencement of Pliocene times (pp. 34 and 37), and 



Fig. 3.-I0 



1 slope of Ben More, We 



that this land disappeared only when the present .\!ps of 

 New Zealand rose towards their maximum height. A 

 relic is believed to remain in the Carboniferous Greenland 

 series (p. 96), which is folded almost at right angles to 

 the trend of the Southern .Alps. The conglomerates of 

 the Oligocene or Miocene Koiterangi series (p. 102) are 

 at first glacial and then fiuviatile, and their pebbles may 

 have descended from the old western highlands. The 

 modern glacial features of the interior furnish material 

 for several striking photographs (Fig. 2). 



Prof. James Park, in Bulletin No. 7 (1909, price is. 6d.), 

 has an equally grand field in the Queenstown subdivision 

 of western Otago. Queenstown lies on the winding Lake 

 Wakatipu, which is fifty miles in length, and close against 

 serrated .Alpine ranges. The main theme of this splendidly 

 illustrated monograph is the evidence for widespread 

 Pleistocene glaciation in the South Island. .AH the signs 

 of confluent glaciers, developing into an ice-sheet, are here 

 brought together in an argument that appears complete. 

 The decline of the ice seems to have been as rapid as in 

 Europe, giving rise to " unparalleled fluviatile activity " 

 (p. 41). The late Pliocene elevation of the country is held 

 to have had considerable influence on the refrigeration, 

 .'ind the Pleistocene subsidence was accompanied by 

 recession of the ice. Striated surfaces, boulder-clays, 

 drumlins, eskers, and all the features familiar in our 

 NO. 2102, VOL. 82] 



hemisphere, are here illustrated from 45° south latitude. 

 Especially remarkable, however, are the terraces carved 

 cut on Ben More above Lake Luna, in a quartzose mica- 

 schist (p. 31), which Prof. Park believes to be unique 

 features of ice-erosion (Fig. 3). The author contributes 

 a short essay on ice-flow and the excavating powers of 

 glaciers. References to the structure of glacier-ice and to 

 experiments on its plasticity would have rendered this 

 more complete, but enough is said to excite interest. The 

 bulletin concludes with an account of local gold-mines, and 

 the maps cover the important areas in which alluvium 

 has been worked, or in which the quartz-reefs seem of 

 promise. As usual, for beauty of illustration and the 

 e.xcellent production of the accompanying maps, these 

 New Zealand bulletins remain unsurpassed. 



G. A. J. C. 



THE LINNEAN SOCIETY'S DISCUSSION ON 



THE ORIGIN OF VERTEBRATES. 

 ■pjL'RING the past fifty years one of the chief tasks to 

 ^-^ which zoologists have applied themselves has been 

 the reconstruction of the phylogeny of the animal kingdom 

 in accordance with the principles of evolution laid down 

 by Charles Darwin. This task is still far from being com- 

 pleted, although no one can doubt that very substantial 

 progress has been made. The evidence 

 is still very imperfect, and every in- 

 crease of knowledge makes more clear 

 the need for extreme caution in draw- 

 ing conclusions. When we think of 

 the familiar comparison of the animal 

 kingdom to a luxuriantly branching 

 tree of which only a few of the top- 

 most twigs are known to us in the 

 living condition, while at the same 

 time we are only able to recover from 

 the past the most fragmentary records 

 of the millions of extinct forms, we 

 are able to realise why it is that most 

 zoologists at present refuse to commit 

 themselves to any particular theory of 

 the origin of vertebrates. Of course, 

 numerous theories have been put for- 

 ward from time to time, but none 

 has met with anything like general 

 acceptance, and there appears to be a 

 widespread feeling that in the present 

 state of our knowledge any such 

 theory is somewhat premature. The 

 discussion of the subject, however, 

 cannot fail to be of use in stimulating 

 thought, and the debate w-hich has 

 occupied the last two meetings of the 

 Linnean Society has naturally aroused 

 considerable interest. 

 Dr. Gaskell, as opener, expounded, in his usual brilliant 

 style, his own particular theory of the origin of vertebrates 

 from an arthropod ancestor. This theory has already been 

 before the scientific public for many years, but has met 

 with little favour amongst professional zoologists, most of 

 whom find it impossible to believe that a highly specialised 

 Limulus-like arthropod could have given rise to such a 

 very difTerent type of organisation as the vertebrate. Dr. 

 Gaskell, as \i well known, bases his argument mainly 

 upon his study of the .Ammocoetes larva of the lamprey, 

 between which and the king-crab he endeavours to draw 

 a very close comparison. 



The keynote of this comparison lies in the central 

 nervous system. The ventricles of the brain, with their 

 lining epithelium, are supposed to represent the arthropod 

 stomach, and the central canal of the spinal cord the 

 intestine. The infundibulum is the ancestral cesophagus, 

 and the neurenteric canal the ancient vent. .Around this 

 tubular foundation the various ganglia of the arthropod 

 nervous, system have become arranged to form the nervous 

 tissue of the vertebrate brain and spinal cord. The 

 original functions of the ancestral alimentary canal have 

 disappeared, and it has been finally replaced by an entirely 

 new structure developed from a respiratory chamber in 

 some pateostracan ancestor. This theory, of course, lands 

 us in a serious difficulty from the embryological point of 



1 Otago. 



