SUMMARY OF CURRENT RESEARCHES. 177 



Columella auris in Amphibia.*— B. F. Kingsbury and H. D. Reed 

 find that in Urodela at least there are two distinct structures in the 

 sound-transmitting apparatus. The first is the columella arising inde- 

 pendently and connected primarily with the squamosal, and in some 

 forms secondarily with the quadrate cartilage. It is probably homo- 

 logous with the hyomandibular-symplectic of fishes. The second is 

 the operculum which seems to arise from a differentiated portion of 

 the ear capsule itself. 



Electric Stimulation and Parthenogenesis!. —Yves Delage has 

 tried to discover how the electricity acts in inducing the partheno- 

 genesis of the eggs of the sea-urchin contained in a fluid through 

 which a current passes. It seems at present difficult to say whether 

 the result should be attributed to the action of static charges or to 

 electrolysis produced by the current. 



& General. 



Mammalian Migrations in Tertiary Times.J — W. D. Matthew 

 considers Deperet's conclusions as to Tertiary migrations, and states 

 his own. These may be summarised [ || = separation : -<--> = union 

 permitting intermigration ; ? = doubtful] — 



Middle Oligocene N. America || Asia -<-->- Europe ? Africa. 

 Lower Oligocene N. America -<-->- Asia •<-->- Europe ? Africa. 

 Upper Eocene N. America || Asia <- -> Europe || Asia -<-->- Africa. 

 Middle Eocene N. America || Asia -<--> Europe || Africa. 

 Lower Eocene N. America -<- -> Asia -<- -> Europe || Africa. 

 Basal Eocene Asia || jST. xlmerica -<- -> Europe || Africa. 



This is, of course, only a working hypothesis. In brief, it is that 

 Asia is and has been the great centre of evolution and dispersion of the 

 dominant mammalian types ; in the other continents, the course of 

 evolution has been — aside from a few well-known exceptions — alter- 

 nately an autochthonic faunal development and a series of waves of 

 migration from the highly progressive faunas of the great Asiatic land 

 mass, according as the continents were separated from or connected 

 with it. The principal exceptions are the Proboscidea, of African 

 origin ; the true Edentates of South American development and doubt- 

 ful origin ; the Camels, of North American origin ; probably other 

 groups, if we knew something about the fauna of the early Tertiary 

 in Asia. 



Structure of Colobus.§— Clara Polak gives a careful account of the 

 structure of the Guereza, and compares it with that of other monkeys. 

 The position of the genus is beside Semnopithecus in the sub-family 

 Semnopithecinse. It is a type intermediate between the lower and 

 the higher Catarrhini. 



*-b 



* Anatomical Record, ii. (1908) pp. 81-91 (7 figs.). 



t Comptes Rendus, cxlvii. (1908) pp. 1372-8. 



t Amer. Journ. Sci., xxv. (1908) pp. 68-70. 



§ Verb. k. Akad. Wet. Amsterdam, xiv. (1908) x. and 247 pp. (57 figs.). 



