214 Presents. [Nov. 26, 



tivity). Hence we conclude that the base becomes negative before the 

 apex, and that its negativity over-lasts that of the apex. 



We do not feel able as yet to explain the triphasic nature of the 

 variation ; it shows, however, that normally the excitatory state at the 

 base lasts longer than at the apex. 



Presents, November 26, 1891. 

 Transactions. 



Berlin : Gesellschaft fur Erdkunde. Yerhandlungen. Bd. XVIII. 



No. 8. 8vo. Berlin 1891. The Society. 



Konis"!. Akademie der Wissenschaften. Abhandlungen. 1890. 



4to" Berlin 1891. The Academy. 



Breslau : Schlesische Gesellschaft fiir Vaterlandische Cultur. 

 Jahresbericht. 1890. 8vo. Breslau 1891 ; Erganzungsheft 

 zum Jahresbericht. Svo. Breslau 1890. The Society. 



Brisbane : Royal Geographical Society of Australasia (Queens- 

 land Branch). Proceedings and Transactions. Vol. VI. 

 Part 2. Svo. Brisbane 1891. The Society, 



Brussels : Academie Royale de Medecine de Belgique. Memoires 

 Couronnes et autres Memoires. Tome X. Fasc. 4. Svo. 

 Bruxelles 1891. The Academy. 



Cambridge, Mass. : Harvard College. Museum of Comparative 

 Zoology. Bulletin. Vol. XVI. No. 10. Svo. Cambridge 

 1891. The College. 



Harvard University. Bulletin. Vol. VI. No. 6. 8vo. Cam- 

 bridge 1891. The University. 



Devonshire Association. Report and Transactions. Vol. XXIII. 

 Svo. Plymouth 1891 ; The Devonshire Domesday. Part 8. Svo. 

 Plymouth 1891. The Association. 



Halle: K. Leopoldino-Carolinische Deutsche Akademie der 

 Naturforscher. Leopoldina. Heft 26. 4to. Halle 1890; 

 Geschichte der Akademie der Naturforscher, 1852 1887. 4to. 

 Halle 1889; Das Vorkommen der natiirlichen Kohlenwasser- 

 stoff- und der anderen Erdgase. 4to. Halle 1890. 



The Academy. 



Verein fur Erdkunde. Mitteilungen. 1891. Svo. Halle a.S. 

 1891. The Society. 



Innsbruck: Naturwissenschaftlich-Medizinischer Verein. Berichte. 



Jahrg. 19. 8vo. Innsbruck 1891. The Society. 



Kew: Royal Gardens. Bulletin of Miscellaneous Information. 



Nos. 55-57. Svo. London 1891. The Director. 



Konigsberg : Physikalisch-Okonomische Gesellschaft. Sclirifteii. 

 Jahrg. 31. 4to. Konigsberg 1891. The Society. 



