r.EPIDOSIRim PARADOXA. 
83 
Text-fig. 9. 
B. 
B.E.3 
Sections transverse to the body of the embryo, illustrating the 
development of the heart, a. Stage 28. Heart markedly U- 
shaped, endothelium and myocardium still separate. The 
straight lines demarcate approximately the different divisions 
of the heart, b. Stage 30. c. Stage 31. A. Auricle, av.r. 
Auriculo- ventricular ridge, which in fig. b extends to the ventral 
curvature of the ventricular part of the heart. B. BuDdus. 
B. Ag. Bulbo-auricular groove. B. B. 1. Bight bulbus ridge. 
B. E. 3. Left bulbus ridge. en. Endothelium. L. A. Left 
auricle, my. Myocardium. jB. A. Bight auricle. F. Ventricle. 
F. M. Ventricular musculature continuous posteriorly with the 
auriculo - ventricular rid ge. 
