640 



SCIENCE. 



[N. S. Vol.. XIV. No. 356. 



cially Hatched Gulls,' and ' On Germinal 

 Selection in Relation to Inheritance,' by 

 Professor J. Arthur Thompson ; ' The Tan- 

 ganyika Problem,' by Mr. J. E. S. Moore ; 

 * The Mechanism of the Frog's Tongue,' by 

 Professor Marcus Hartog and Mr. Nevil 

 Maskeleyne ; ' Dimorphism in the Foram- 

 inifera,' by Mr. J. J. Lister; 'The Habits 

 and Life Histories of some Sarawak Insects,' 

 by Mr. R. Shelford ; ' On a Large Nema- 

 tode Parasite in the Sea-urchin,' by Dr. J. 

 F. Gemmill ; ' On the Youngest Known 

 Larva of Polypterus,' by Mr. J. S. Bud- 

 gett ; on ' The Land Crabs of a Coral 

 Island,' by Mr. L. A. Borradaile; and on 

 'The Fauna of an Atoll,' by Mr.C.F. Cooper. 

 A very pleasing incident of the meeting 

 was the announcement of a generous gift, 

 amounting to £3,500, from a donor who 

 wished to remain anonymous, towards the 

 equipment of the Scottish Marine Biological 

 Station, now established at Millport on 

 Cumbrae Island in the Firth of Clyde. The 

 station, which was visited by a large num- 

 ber of the members of the Section, is ad- 

 mirably situated and is accomplishing most 

 excellent work. The present gift will be 

 devoted to an extension of the buildings so 

 as to afford quarters for those who may be 

 working at the station. 



J. PLAYFAtR McMuRRICH. 



University of Michigan. 



ADDRESS OF THE PRESIDENT OF THE AN- 

 THROPOLOGICAL SECTION OF THE 

 BRITISH ASSOCIATION, IL 



The insular district in the fetal brain is 

 a depressed area of an elongated triangular 

 form. The general surface of the cerebrum 

 occupies, all round about it, a more ele- 

 vated plane, and thus the insula comes to 

 be bounded by distinct walls, like the sides 

 of a shallow pit dug out in the ground. 

 The upper wall is formed by the lower 

 margins of the frontal and parietal lobes, 

 the lower wall by the upper margin of the 



temporal lobe, and the front wall by the 

 frontal lobe. From each of these bounding 

 walls a separate portion of cerebral cortex 

 grows, and these gradually creep over the 

 surface of the insula so as to overlap it, 

 and eventually completely cover it over 

 and exclude it from the surface, in the same 

 way that the lips overlap the teeth and 

 gums. That which grows from above is 

 called the fronto-parietal operculum, while 

 that which grows from below is termed the 

 temporal operculum. These appear very early, 

 and are responsible for closing over more 

 than the hinder three-fourths of the insula. 

 The lower or temporal operculum is in the 

 first instance more rapid in its growth than 

 the upper or fronto-parietal operculum, and 

 thus it comes about that when their mar- 

 gins meet more of the insula is covered by 

 the former than by the latter. So far the de- 

 velopment is apparently precisely similar 

 to what occurs in the ape. The slit or fis- 

 sure formed by the approximation of the 

 margins of these two opercula is called the 

 Sylvian fissure, and it constitutes a natural 

 lower boundary for the parietal and frontal 

 lobes which lie above it. At first, from 

 the more energetic growth of the lower 

 temporal operculum, this fissure slants very 

 obliquely upward and backward, and is 

 very similar in direction to the correspond- 

 ing fissure in the brain of the ape. But in 

 the human brain this condition is only 

 temporary. Now begins that downward 

 movement of the parietal lobe and back 

 part of the frontal lobe to which reference 

 has been made. The upper or fronto- 

 parietal operculum, in the later stages of 

 fetal life and the earlier months of infancy, 

 enters into a growth antagonism with the 

 lower or temporal operculum, and in this 

 it proves the victor. The margins of the 

 two opercula are tightly pressed together, 

 and, slowly but surely, the fronto-parietal 

 operculum gains ground, pressing down the 

 temporal operculum, and thus extending 



