IQg K. MITSUKURI; 



THE CLASSIFICATION OF VERTEBRATE EGGS. 



The considerations set f<jrth in the preceding pages make 

 necessary a reclassification of the eggs of Yertebrata. I append below 

 a table of classification such as I conceive it : — 



I. Primary Type :— 



Archi-Holohlastic : — Aiuphioxus. 

 Froto-Holohlastic : — Eo-o-s that have never 



Co 



{icquired a large yolk-mass and hence 

 have retained the primary condition 

 nearest to Amphioxus. Cijclostomi. 



Proto-Merohlastic : — (a) Eggs that have ac- 

 Cjiiired a large primary yolk-mass. 

 Elasniolmuichii, 

 (h) or eggs that having lost the large pri- 

 mary yolk-mass have at least retained 

 the meroblastic mode of se2:mentation. 

 Teleostei. 



Meso-Holohlastic : — EsfS's that had at one time 

 acquired a large yolk-mass but have lost 

 it, returning to the holoblastic condition. 

 Ainphihia (/) 



II. Secondary Type:— 



Meta-Mcrohlastic : — Eg-o-s that had at one time 

 acquired a large primary yolk-mass, had 

 then lost it, and now have acquired a 

 large yolk-mass for the second time. 

 BeptUia, Arcs. 



