1916.] The Third Indian Science Congress. cxxv 



led to refer the topi-kallu to the " dolmen period." The hat-stones un- 

 doubtedly belong to an advanced type of civilization as could be mad- 

 out from their excellent finish and graceful appearance. Architectural 

 style is but the character of the nation and of the epoch expressed in 

 wood, stone or brick. The chronological sequence of Logan thus modi 

 fied would be as follows : — 



Probably synchronous 



I. Dolmens, menhirs, cromlechs, etc. 



II. Excavated caves. 



III. (a) Caves with massive urns (umbrella- 



stones), and massive sepulchral 

 urns without caves : 

 (b) hat-stones. 



IV. Modern sepulchral urns of a small size. 



Xo definite 



chronological sequence can be traced in the evolu- 

 tion of megalithic monuments of different countries, much less can their 

 appearance, construction, and contents be said to indicate a phase or 

 contemporaneity. The dolmens of Africa often contain objects character- 

 istic of the Iron Age, whereas in India, the practice of erecting megali- 

 thic structures still obtains amongst some of the aboriginal tribes, such 

 as the Mundas, Kuruvas, and Khasias. 



LECTURES. 



Dr. E. H. Hankin's lecture on " The Evolution of Flying 

 Animals." 



The wings of insects were shown to have developed from tracheal gills 

 which were leaf-like appendages borne in pairs on each body-joint of the 

 primitive insect. A picture was shown of one of the earliest known fossil 

 insects. Each of the joints of the thorax carried a pair of wings. Conse- 

 quently the animal was six winged. The succeeding joints of the abdo- 

 men were each provided with a pair of tracheal gills. The wings of these 

 primitive insects have been shown to resemble in their structure in 

 certain respects tracheal gills and to differ in the same respects from the 

 wings of modern insects. 



Passing on to the question of the origin of flying fishes it \\ as pointed 

 out that many fishes scuttle along the surface of the water to avoid their 

 enemies. Fishes having such habits have in many cases evolved into 

 flying fishes. An illustration was shown of a fossil flying fish in which * 



the wings were attached below the level of the centre of gravity instead 

 of above this point as is the case in modern flying fishes. One would 

 expect such a position of the wings to conduce to lateral instability. 



Reasons were given for believing that the ancestor of birds was a 

 dinosaurian reptile. The most primitive bird known, the u Archaeop- 

 teryx," was described and its reptilian characters were explained. Each 

 wing was provided with three claws which for reasons described in detail 

 were supposed to be functional. In modern birds the second and third 

 of these digits were provided with large quill feathers which are used in 

 steering from side to side. Thus the muscles that moved the hand in the 

 ancestral reptile were adapted for purposes of flight in the bird. The 

 muscles that moved the hand were also adapted for this purpose in the 

 group of fossil- flying reptiles known as pterodactyls. In these animals 

 the wing is supported on an enormously enlarged finger. In bats also the 

 hand is used to form the wing, all the fingers being elongated and en- 

 larged to support the volant membrane. 



In each case it is probable that the power of gliding preceded that of 

 flapping and that the power of gliding in a straight line preceded the 



