336 Puget Sound Marine Sta. Pub. Vol. 1, No. 28 



PLATE 76 



os=auditory sac 

 6/=blastopore 

 6«^nuclei of blastoderm 

 gr=germ ring 

 m«=mesodermal somites 

 /?=periblast 

 *c7n=seeondary caudal mass 



Fig, 19. Surface view of 10-day egg from side; advancing germ 



ring; embryo. X 7.6. 



Fig. 20. Surface view of 11 -day egg from side; advancing germ 



ring; embryo. X 7.6. 



Fig. 21. Surface view of 12-day egg from side; embryo; yolk blasto- 

 pore. X 7.6. 



Fig. 22. Surface view of 13-day egg; embryo complete; blastoderm 

 covering entire yolk. X 7.6. 



Fig. 23. Section thru 6-hour disk; 2-celled stage. X 43.8. 



