CONTRIBUTIONS FROM THE 



Botanical Laboratory of the University 

 of Pennsylvania 



VOL. II, NO. 3. 



Printed on the Mrs. James Mcmanes Fund. 



A Comparative Study of the Cytology and 

 Movements of the Cyanophyceae. 



(WITH PLATES XXIII-XXV.) 



Thesis presented to the Department of Philosophy. University of Pennsylvania, 



May 1903, in partial fulfilment of requirements for 



the Degree of Doctor of Philosophy. 



Read before the Botanical Society of Pennsylvania, October i8th, 1902. and 

 May isth, 1903.* 



By Orville P. Phillips, M. S., Ph. D. 



The problem of heredity has been attacked from many- 

 sides. Various theories concerning the transmission of char- 

 acteristics, whether acquired or otherwise, have been given 

 to the world, and as many have been withdrawn or proven 

 untenable, at least by some authorities. From Thales to 



* In view of the recent appearance of three valuable contributions 

 to the above subject, it may be stated that Dr. Phillips' completed 

 thesis was placed in my hands on May 3d, 1903, and has been in my 

 care since. Its publication has been vmavoidably delayed till now, 

 but no alterations have been made on it. While the views here set 

 forth can claim no priority over those already published, their appear- 

 ance may aid in the settlement of disputed points. — ^J. M. Mac- 

 rARLANE, Editor. 



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