1916.] The Third Indian Science Congress, oxvii 



exist ; at the same time to define and demarcate the characteristics and 

 limits of the chief varieties, a matter which till now lias been in a dis- 

 tinctly chaotic condition. 



The Geographical Distribution of Indian Earthworms. 



By J. Stephenson, I. M.S. 



The modes of spreading in the Oligochaeta differ very considerably 

 in the case of freshwater and terrestrial forms. Freshwater forms spread 

 with such ease and so widely that the facts of their distribution are 

 practically useless for zoogeography. The case is quite different with 

 terrestrial forms. 



The former conection by land of India and Australia, and India and 

 New Zealand, is demonstrated by a comparison of the earthworm fauna- 

 but it is not necessary to suppose, with Michaelsen, that the land connec- 

 tion must have extended across the Bay of Bengal ; recent discoveries in 

 the Abor country renders it possible to suppose that the Oligoehaete im- 

 migrants took a path round the head of the Bay. 



The former connection between India and Africa (Madagascar) i- 

 documented by fewer faunistie records ; though these have recently been 

 added to by the discovery in Bombay of a genus which may be looked on 

 as a direct descendant of a form at present peculiar to Madagascar. 



Indian Freshwater Prawns of the family Atyidae. 



By Stanley Kemp. 



The author gave a brief account of the principal characteristics and 

 distribution of the Atyidae in India and discussed Bouvier's theory of the 

 mutational origin of certain forms. Recent investigations tend to show 

 that the Atyid fauna of the Andaman Islands is one of peculiar interest, 

 comprising a remarkable combination of forms similar in character to 

 those on which Bouvier founded his theory. 



Physics Section. 

 (Chairman— Mr. G. C. Simpson, F.R.S.) 



The meetings of the Physics Section were very successful, but owing 

 to the large number of excellent papers which had to be considered it was 

 necessary to cut down as much as possible the discussion of each. 

 Although the discussions were short they were very much to the point 

 and considerable useful work was done in the section. The chairman 

 prefaced his paper on " Some problems of Atmospheric Electricity " with 

 a few general remarks on the effect of the war on the output of 



research in physics and emphasized the necessity for taking the oppor- 

 tunitv of a decrease in new work to review our present position. 



Some Problems of Atmospheric Electricity.— By 



G. C. Simpson. 



Five problems of atmospheric electricity were discussed. 



(1) It w r as shown that although there appears to be sufficient radio- 

 active matter in the earth and atmosphere to account for the ionisation 

 of the air over the land, this is not so over the sea where there is little 

 radio-active matter in the air and practically none in the sea. 



(2) Recent observations made in balloons indicate that a very 

 penetrating radiation enters the earth's atmosphere from above : the 

 origin and nature of this radiation were discussed. 



