THE KANSAS UNIVERSITY 

 SCIENCE BULLETIN 



Vol. IX, No. 12.] DECEMBER, 1914. [v1 ho xk s no e ! 2 



Studies Upon the Number of Germ Cells 

 of Certain Fish. 



Fundulus heteroclitis. — Nellie Taylor. 

 Embiotica jacksoni. — Cora M. Downs. 



[Contribution from the Zoological Laboratory No. 214.] 



Explanatory Note. — B. M. Allen. 



The purpose of the following papers is to show the typical number 

 of germ cells of certain vertebrates during certain early stages in de- 

 velopment in which there is for a long period no multiplication. It is be- 

 lieved that this is a matter of considerable theoretical interest. Each 

 species of vertebrates has a typical average number of germ cells present 

 at this time, and it is thought that future investigation may perhaps show 

 that the final number of germ cells produced in a yield will prove to be 

 some multiple of this. Upon such an assumption there is considerable in- 

 terest in comparing the number of germ cells in different individuals. This 

 work was done under my supervision and I feel full confidence in the re- 

 sults given below. This work is in line with similar counts made by Eige- 

 mann, Beard and by myself upon various forms of vertebrates. These 

 counts of the germ cells of these teleosts are of considerable interest. This 

 is especially true in the case of Fundulus heteroclitis, a form that has 

 served for so much valuable work along experimental lines. 



The eggs and embryos of Fundulus heteroclitis were collected 

 at Woods Hole, Mass. They were preserved and fixed in 

 Zenker's fluid and 5 per cent formalin. 



The material of Embiotoca jacksoni was gathered at San 

 Diego, Calif., fixed in bichromate-acetic fluid and preserved in 

 70 per cent alcohol. 



Paraffin sections were cut the thickness of 10 micra, and 

 stained in iron-hsematoxylin and orange G. Great care was 



Received for publication December 6, 1914. 



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