The Ohio ^aturalisf^ 



and Journal of Science 



PUBI^ISHED BY 



The Biological Club of the Ohio State University. 

 Volume XV. NOVEMBER, 1914. No. 1. 



TABLE OF CONTENTS 



Humphrey— A Cytologieal Study of the Stamens of Srailax herbacea 357 



KOSTIR— Additions to the Known Orthopterous Fauna of Ohio 370 



Jennings— Publications of the Ohio Biological Survey 374 



McAvoY— Meeting of the Biological Club 376 



A CYTOLOGICAL STUDY OF THE STAMENS OF SMILAX 



HERBACEA* 



Lillian E. Humphrey. 

 INTRODUCTION. 



There seems to be a general agreement among the various 

 investigators of the reduction division, that there is a pairing 

 and conjugating, in the first reduction division, of the univalent 

 chromosomes to form bivalents, but there is a considerable 

 diversity of opinion as to the time of the pairing and fusion. 

 Allen, Gregoire, Overton and many others hold the view that there 

 is a side to side pairing of the chromatic elements occurring usually 

 about the time of "synapsis." De Vries also claimed that there 

 is a side to side pairing, but was not certain when it occurred, 

 although it was some time before the separation of the halves 

 of the bivalent chromosomes. As a proof of this theory it was 

 held that, since a longitudinal split of the spirem is discernible in 

 the early stages of the reduction division, the double spirem was 

 the result of a conjugation of two simple spirems. But according 

 to Schaffner, Farmer and Moore, Mottier and others the early 

 split js a longitudinal division of the same nature as that which 

 occurs at each vegetative karyol-dnesis. The pairing of the 

 univalents according to this view must occur very early, before 

 the formation of the spirem; and the protochromosomes, which 

 in some species are rather definite masses and approximate the 

 reduction number of chromosomes, probably represent the end 

 of the stage when the pairing occurs. 



* Contribution from the Botanical Laboratory of the Ohio State 

 University, No. 85. 



357 



