MUSEUM OF COMPARATIVE ZOOLOGY. 97 



PLATE III. 



.Fig. 9. Cross section cut f mm. from anterior end of embryo, seven days old, 



1^ mm. long. 

 " 10. Cross section cut -^g mm. from anterior end of embryo, seven and one half 



days old, If mm. long. 

 " 11. Cross section cut ^^ mm. from anterior end of embryo, eir/Iit days and 



four hours old, 2f mm. long. 

 " 12. Cross section cut i mm. from anterior end of fundulus embryo, four and 



one half days old, 2j'jy mm. long. 



PLATE IV. 



Fig. 13. Cross section of a fundulus embryo, six hoars younger tiian that of Figure 

 12. Cut ill tiie same region. 

 " 14 and 15. Cross sections of tlie same fundulus embryo as tiwit of Figure 13, 



and from nearly tlie same region. 

 " 16. Cross section through tlie heart of a cod embryo, niiie and one half days 

 old. 



PLATE V. 



Diagram of an apparatus for batching fisli eggs. For explanation, see text, 

 pages 93, 94. 



