344 Some Phases of the Gastrulation of the Horned Toad 
marg. bl, po. can.nent. 
itz poe 
SORC RUSH 
eee 
Fig. 15. 
Caniaient. qigbls @hbt 
Figs. 10-15. Cross-sections of an embryo of about the same age as Fig. 5, 
probably a little older. Dl. ’po., blastopore; can. n’ent., canalis neurentericus; 
cd. d., chorda dorsalis; e.’bl., epiblast; h. 'bl., hypoblast; marg. bl.’po., mar- 
gin of blastopore; ms. 'Dl., mesoblast; < 200 diameters. 
