h 



I--F 



A. Lemur 



b.?l6, 



_h e 



£. Mud- puppy 



F.D<#ish 



Figure 65. Corresponding early embryonic stages from a series of typical 

 vertebrates, lateral view. Magnified about 5 diameters, e, eyeball; I, first 

 branchial groove; h, heart; F, fore limb; H, hind limb. Body segments 

 (somites) are visible throughout the trunk region. 



A. Embryo of lemur (Tarsias), about 8 millimeters long. After Keibel- 

 Hubrecht. 



B. Pig embryo 7.5 millimeters long. After Minot. 



C. Chick embryo 7.6 millimeters long. After Keibel and Abraham. 



D. Embryo of lizard (Lacerta) 5.9 millimeters long. After Keibel-Peter. 



E. Embryo of mud-puppy (Necturus), about 9(?) millimeters long. After 

 Keibel-Platt. Abdomen distended by large yolk mass. 



F. Embryo of dogfish (Acanthias), 9 millimeters long. After Keibel-Scam- 

 mon. The yolk sac has been removed. 



