January 4, 1906] 



NA TURE 



239 



This paper is one of a series in which it is hoped to deal 

 with the cerebral cortex of the various orders of mammals 

 so far as material is available, the primary object of the 

 research being to endeavour to shed some further light 

 upon the significance of the mammalian neopallial lamin- 

 ation. In this natural order the brains of the mole (Talpa 

 europea), shrew (Sorex vulgaris), and hedgehog (Erinaceus 

 europeus) have been exhaustively studied. 



The neopallium of these animals has been mapped out 

 into various areas, which on the dorso-lateral and mesial 

 aspects appear to present (i) " motor," (2) general sensory, 

 and (-,) undifferentiated or unspecialised characteristics, the 

 two former being in every way the best developed neopallial 

 regions. On the postero-mesial aspect a field has been 

 delimited which possesses sensory features ; a portion of 

 this is unspecialised, and the remainder is believed to repre- 

 sent the cortical distribution of the optic and fifth sensory 

 nerves respectively. Certain differences in the extent and 

 state of development of these various areas occur in the 

 -i 11 1.1I animals, and these agree with certain differences in 

 their habits. 



I he total depth of the cortex in the best developed regions 

 differs in the three animals, yet the relative depth of the 

 separate layers is about the same in all. Micrometrii 

 measurements of the cortex of the mole have been made 

 by Dr. Bolton, and these have been compared with the 

 latter's measurements of the cortical layers in the develop- 

 ing human foetus and the normal human adult. Dividing 

 the cortex into the portions above and below the granular 

 laver, it is found that the increase in depth of the human 

 cortex as compared with that, say, of the mule is very 

 largely due to increase in the " supra-granular " (i.e. the 

 true pyramidal) layer. 



I In conclusions as to the functional significance of the 

 neopallial primary cell layers in the Insectivora and in 

 mammals belonging to other natural orders so far ex- 

 amined form a complement to those advanced by Bolton. 



I In " infra-granular " layer (iv. and v.), omitting the 

 constituent cells which possess motor or analogous func- 

 tions, is concerned especially with the associations necessary 

 lor the performance of the instinctive activities, the 

 " supra-granular" (ii.) with the higher associations (" in- 

 telligence "), the capacity for which is shown by the 

 educability of the animal. In practical animal behaviour 

 the two sets of processes are probably more or less n in- 

 stantly interwoven, the higher activities (supra-granular 

 layer) coming to the aid of the lower so far as the capability 



ii 1 he animal allows. In the case of lower mammals, e.g. 



Insectivora, the limits of this capability are comparatively 

 soon reached, and correspondingly these mammals possess 

 a relatively pour " supra-granular " layer. 



Anthropological Institute, December 19, 1505. — Prof. \V. 

 Gowland, president, in the chair. — The origin of Eolithic 

 flints from natural causes: S. H. Warren. Mr. Warren 

 classified eoliths as follows: — (1) Flints with battered 

 surfaces formed by prolonged concussions; (2) flints with 

 flaked surfaces formed by sharp percussions; (3) Hints with 

 chipped edges formed by (a) indiscriminate battering, 

 (/>l perpendicular pressure. The possible causes of the pro- 

 duction of eoliths were considered by Mr. Warren to be: — 

 («) human agency ; (h) wave action ; (c) water abrasion by 

 streams, rivers, floods; (d) soil abrasion by the pressure 

 and movement of soil creep and foundering ; (e) the drag 

 of ice ; and (/) wear and tear on the surface of the ground. 

 The eoliths of the first class, as defined above, may 

 obviously be due to water abrasion. Those of the second 

 1 lass bear evidences of percussion-flaking, acting along the 

 lines of least resistance, but show no control-working upon 

 a definite design. It is concluded that these forms, 

 together with those having indiscriminately battered edges, 

 .ire likewise due to water abrasion. It is noteworthy that 

 these classes are characteristic of river gravels of various 

 ages, and may be reproduced by artificial rolling. The 

 Hints with definitely pressure-chipped edges include the 

 typical " plateau implements " of Sir J. Prestwich. The 

 chief forms are a general chipped edge, and the notch, 

 either single or in various combinations, such as the double 

 notch with intervening point. It is found by experiment 

 that these are the forms produced bv the fortuitous pressure 

 of one flint against another. The angle of chipping and 



NO. l888, VOL. 73] 



the type of the fractures are also identical in the case ol 

 the experimental productions and the plateau Hints. These 

 pressure-chipped eoliths are characteristic of hill-drifts 

 which have suffered from the movement of soil-creep nil 

 foundering, and it is concluded that this is the cause 'I 

 the chipped edges. This process is named " soil abrasion " 

 in contradistinction to water abrasion. Collateral evidence 

 of these differential soil movements under pressure is 

 furnished by the frequent association with the eoliths of 

 the hill-drifts of Hints with surfaces striated in all direc- 

 tions. Subsidiary causes of the pressure-chipped eolith-. 1 „- 

 those which have operated in certain special cases, are the 

 drag of ice and wear and tear on the surface of the 

 ground, including the impact of the hoofs of animals. 



I 1 UNBURGH. 



Royal Society, December 4, 1905. — Lord Kelvin, presi- 

 dent, in the chair. — The development of the skull and 

 visceral arches in Lepidosiren : W. K. Agar. The material 

 for this investigation had been collected by Prof. Graham 

 Kerr in the Chaco, and by the late Mr. J. S. Budgett in 

 the Gambia. The chief points established were as 

 follows : — The development of the notochord underwent a 

 curious modification, the front end disintegrating at an 

 early stage and being replaced by a forward growth of the 

 remaining part of the chorda. The quadrate was from 

 the first continuous with the trabecula, anil there was no 

 hyomandibular. A vestigial palato-pterygoid bar was pre- 

 sent. The general development of the skull resembled the 

 process in the Urodeles, especially as regards the occipital 

 region and nasal capsules. There were two pairs of upper 

 labial cartilages. In the change from the larval to the 

 adult form there was no absorption of cartilage, but the 

 chondrocranium showed a steady increase in completeness. 

 — Perturbations in longitude of Neptune by the hypo- 

 thetical planet: Prof. George Forbes, F.R.S. About 

 twenty-five years ago the author had deduced evidence from 



the distribution of the aphelia ol itary orbits that there 



existed a planet of considerable mass beyond the orbit of 

 Neptune, and the existence of such a planet was now 

 generally accepted by astronomers. In the present paper, 

 by means of calculations based upon certain assumptions 

 as to position and mass of the hypothetical planet, Prof. 

 Forbes discussed the growing discrepancies between the 

 observed longitudes of Neptune and those assigned by the 

 theories both of Leverrier and Newcomb. The present 

 configuration of the two planets was not the best to bring 

 out clearly the nature of the perturbation, but he thought 

 that in ten years sufficient material would be in hand 10 

 enable us to make a serious effort In fix the position of 

 the ultra-Neptunian planet. — Exhibition of two lantern 

 slides of zoological interest : Prof. D. J. Cunningham, 

 F.R.S. The one showed a group of monkeys in the Dublin 

 Zoological Gardens sitting in newly fallen snow without 

 the least discomfort ; from the beginning of their captivity 

 they had lived in the open air. The other showed a young 

 marmoset clinging in its peculiar fashion to the back of a 

 white rabbit which had acted as foster-mother from the 

 start of the marmoset's individual life. 



December 18, 1905. — Dr. R. H. Traquair, F.R.S., vice- 

 president, in the chair. — Library aids to mathematical 

 research: Dr. Thomas Muir, F.R.S. After a critical dis- 

 cussion of the various bibliographical aids to the mathe- 

 matical student, the author proceeded to point out the 

 shortcomings in the equipment of the most important 

 scientific libraries in Edinburgh and Glasgow. Out of 

 sixty-seven important mathematical serials, only thirty-four 

 were to be found in Edinburgh and Glasgow; and of the 

 thirty-one to be found in Edinburgh, twenty-one were 

 duplicated in the university and Royal Society libraries. 

 Dr. Muir hoped that by some system of cooperation 

 between the Edinburgh libraries, or even between Edin- 

 burgh and Glasgow, every mathematical serial published 

 in Europe and America would he made available to mathe- 

 matical workers. At present historical research was 

 absolutely debarred. — Preliminary note regarding an ex- 

 perimental investigation into the effects of varying diets 

 upon growth and nutrition : Dr. Chalmers Watson. The 

 experiments consisted in feeding colonies of rats upon 

 various diets, namely, (1) skim milk and bread; (2) rice; 



