EMBRYOLOGY AND LARVAL DEVELOPMENT OF TELEOSTEAN FISHES. 425 



of the embryo also are somewhat obscured in the living material. As far as may be 

 observed, however, these stages conform in all essential respects to the corresponding 

 stages above described in the egg of the Cyprinodon variegatus. 



The later development of the embryo advances rapidly. At 48 hours after fertiliza- 

 tion (fig. 48) the embryo is well formed and already shows six to eight somites. At 60 



Fig. 4S.— Egg 48 hours after (ertilization. 



Fig. 49. — Egg 60 hours after fertilization. 



10^ 



Fig. 50. — Egg 9b hours after fertilization. 



GOBIOSOMA BOSCI. 



hours after fertilization (fig. 49) the embryo has increased materially in size. Its length 

 exceeds three-fourths the length of the major axis of the egg membrane. The yolk mass 

 remains opaque, but the embryo is highly transparent. No pigment is as yet apparent. 





•--> 



Fig. si. — ^Newly hatched fish, actual length 2 mm. 



Fig. 52. — Larval fish j mm. in length. 



:^^^'~'^^^^^ 



Fig. si. — Young fish lo mm. in length. 



GOBIOSOMA BOSCI. 



As the time of hatching approaches (fig. 50) the length of the embryo exceeds the length 

 of the major axis of the egg membrane and the tail becomes bent upon itself. The embryo 

 remains highly transparent, only a few small pigment spots appearing in proximity with 

 the vent. 



