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NA TURE 



427 



successful attack upon the difficult problem of the origin of 

 mammals it was necessary first to reject the hypothesis, brilliantly 

 formulated by Huxley in 1880, of a genetic succession between 

 Monolreme, Marsupial and Placental types, since this could not 

 be supported by either palaeontology or comparative anatomy. 

 He explained the law of adaptive or functional radiation whereby 

 mammals have repeatedly diverged from small unspecialised 

 focal types into aquatic, arboreal, volant, herbivorous and 

 carnivorous orders, and pointed out that the balance of evidence 

 among the mammals, as among the reptiles, is in favour of all 

 aquatic types being secondarily evolved out of land types. All 

 carnivorous and herbivorous types were over-specialised, or in a 

 cul de sac of development, so that it was probable that the 

 Promammal was a small terrestrial animal, either insectivorous 

 or omnivorous in its habits. There was abundant evidence that 

 many of the small mammals of the Middle and Upper Jurassic 

 were not Marsupials, but insectivorous Placentals, fulfilling all 

 the conditions required for the ancestry of the living Insectivora 

 and the Creodonta, and, through the latter, of all the higher 

 existing types of mammals, including man. Leaving the 

 mammals, he remarked that the Theriodonts and Gomphodonts 

 were surprisingly Promammalian in type, and that we were 

 strongly tempted to connect the latter division, which is 

 herbivorous, directly with the herbivorous Mnnotremes and 

 Multituberculates. The large size and high specialisation of 

 these types was, however, opposed to this view. In concluding 

 he said that South Africa was at the present time a centre of the 

 highest interest, and that for further developments of the 

 problem of the origin of mammals we must probably look to the 

 rich fauna of the Karoo beds. 



In the discussion which followed. Prof. Marsh said that the 

 mammals themselves comprised so many different groups that it 

 was a fair question whether all these had a common origin. 

 The supposed resemblance between the teeth of the Anomodont 

 reptiles and those of mammals was not confined to one group. 

 The extinct crocodile Notosuclnis recently found in Patagonia 

 has the three kinds of teeth well developed ; and in the genus 

 Triceratops, of the Dinosaurs, all the teeth have two roots — a 

 supposed mammalian character ; but no one had yet attempted 

 to derive the mammals from the Crocodiles or the Dinosaurs. 

 Prof. Marsh declined to admit that any reptiles possess a true 

 double condyle, since in the known forms the two parts are in 

 contact below, forming essentially a single cordate condyle, as 

 in some of the Chelonia. Again, all reptiles have a quadrate 

 bone, which may be small and partly enclosed in the squamosal, 

 but never lost. No known mammal has a true quadrate, and the 

 attempts to identify that bone in the mammalian skull have not 

 been successful. Most important of all, the lower jaw of all reptiles 

 is composed of several pieces, even the Anomodonts showing 

 the sutures distinctly. There was, said Prof. Marsh, a great 

 gulf between mammals and reptiles which it was at present diffi- 

 cult to bridge over. Prof. Haeckel then spoke in high terms of 

 the excellent palxontological work which was being carried on 

 in America, and the value of the recent discovery of annectent 

 forms. He was inclined to adhere to the view of the origin of 

 all Placental mammals from Marsupials. Mr. A. Sedgwick 

 said that no assistance could be looked for in the direction of 

 embryology, and in support of this statement showed that al- 

 though we regard the horses as descended from pentadactyle 

 ancestors, the embryos show no more details of limb structure 

 than the adult ; and that although birds are admitted to have 

 lost their teeth in the process of evolution, no rudiments of teeth 

 are found in the embryo. He referred to the profound modifi- 

 cation of embryonic development which varying amounts of yolk 

 in the egg may cause ; and he doubted whether any of the ex- 

 tinct forms known to us ought to be considered as ancestors of 

 existing forms. He would like to see all the lines of the 

 genealogical tree running down to the Pre-Cambrian without 

 joining. Prof. Hubrecht also spoke on behalf of the embry- 

 ologists, and pointed out that the one great distinction between 

 the Ichlhyopsida on the one hand, and 'the Sauropsida and 

 Mammalia on the other, was the presence of the amniotic 

 envelope in embryos of the latter and its absence in the former. 

 Our ignorance of the development of the extinct forms prevented 

 him from accepting the doctrine of descent as propounded by 

 pahvontologists. He referred to Prof. Hill's discovery of a 

 definite deciduous placenta in Pe> ameks, and to the less com- 

 plete placenta of Phascolantos, and concluded by expressing his 

 doubts as to the intermediate position occupied by the Mar- 

 supials between the Monotremes and the Placental mammals. 



Prof. Newton said that he took a more hopeful view of the 

 question than the last two speakers, and that he looked in the 

 direction of comparative anatomy and pala'ontology, rather than 

 embryology, for the solution of the problem of the "Origin of 

 Mammals." 



In the afternoon at the Senate House the honorary degree of 

 Doctor of Science was conferred on several members of the 

 Congress and of the Congress of Physiologists. The speeches 

 delivered hy the Public Orator upon this occasion are printed 

 at the end of this report. Prof. Kowalevski, whom it was also 

 proposed to honour, was unfortunately prevented from attending 

 the Congress. 



A paper on " Fishery Statistics," by Prof. Mcintosh, was 

 read in Section B. 



On Friday morning, Prof. Haeckel, discoursing on "The 

 Descent of Man," said that the monophyletic origin of all 

 Mammalia from the Monotremata upwards to Man is at present 

 no more a vague hypothesis, but a positively established fact. 

 All the living and extinct Mammalia which we know, are de- 

 scended from one single ancestral form, which lived in the 

 Triassic or Permian period ; and this form must be derived from 

 some Permian or perhaps Carboniferous reptile (allied to the 

 Progonosauria and Theriodontia), and the latter from a Carbon- 

 iferous Amphibian (Stegocephalia). These latter are descended 

 from Devonian fishes, and these again from lower Vertebrates. 

 Much more difficult is the question of the origin of the great 

 Vertebrate-Stem, and its descent from Invertebrates. But these 

 questions are not so important as the fact that Man is a member 

 of the Primate-Order (Linne), and that all Primates descend 

 from one common stem (Huxley). Zoology may be proud to 

 have proved this fact, based on the theories of Lamarck (1809) 

 and of Darwin (1859). 



Prof. Marey explained why the subject of animal locomotion 

 could not be investigated from the physiological standpoint only, 

 but that a minute study of comparative anatomy was also essen- 

 tial. He exhibited numerous instantaneous photographs of 

 horses in successive phases of movement. 



Mr. W. L. Duckworth gave an account of the anatomical 

 researches he is at present making on the Gorilla and other 

 Anthropoid apes. 



M. E. Dubois made some "Remarks on the brain-cast of 

 Pithecanthropus erectus." He called attention to the scapho- 

 cephalic nature of the skull, and the consequent narrowness of 

 the frontal region of the brain and the strong impressions of the 

 frontal convolutions on the interior of the calvarium. The 

 author repudiated the suggestion that the skull was a micro- 

 cephalic anomaly. The femur which was found associated with 

 the skull suggested bipedal locomotion, but there were indica- 

 tions in that bone of an arboreal habit such as are not found in 

 the human femur. He showed how by comparison of human 

 thigh bones with known corresponding body-weight he had 

 estimated from the size of the femur of Pithecanthropus that 

 its body-weight must have been 70 to 75 kilos. He then 

 deduced the size of the whole brain (850 c.c,) from that of the 

 internal cast of the calvarium, and from this the weight of the 

 brain (750 grams). His ultimate conclusion was that in 

 a man, an anthropoid ape and a Pithecanthropus of the same 

 body-weight, the brain of Pithecanthropus would be twice as 

 large as that of the ape, and half the size of that of the man. 



In the afternoon in Section A, Prof. MacBride read a paper 

 on the " Origin of Echinoderms." He pointed out that the type 

 of larva common to the Asteroids, Ophiuroids, Echinoids, and 

 Holothuroids probably represented a free-swimming bilateral 

 ancestor of simple organisation. The main object of his paper 

 was to consider the transformation of the bilateral into the radial 

 form. Since the right water-vascular rudiment remained small, 

 a main factor in the metamorphosis was the unequal develop- 

 ment of the two sides. Where, as in Crinoids, a fixed stage 

 succeeded the pelagic stage, bilateral symmetry ceased to be of 

 importance to the animal ; but a radial arrangement of external 

 organs was advantageous, and hence incipient inequalities in the 

 sides would be made use of to produce the radial arrangement. 



Sir Herbert Maxwell then read a paper on " Recent Legislation 

 on Protection of Wild Birds in Great Britain," in which he 

 pointed out that with regard to migratory birds the question of 

 protection was of international importance, and he referred to 

 the recent letters in The Times complaining of the diminution 

 in the number of swallows in our southern counties owing to 

 their wholesale slaughter in the south of France. He discussed 

 the relative merits of absolute protection in certain areas, the 



NO. 1505, VOL. 58] 



