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DEYELOPMENT OF THE FROG 

 LJ 



Fig. 33 — ^A 12 mm. tadpole dissected from the ventral surface 

 to show the heart, the internal gills, the branchial vessels, and the 

 head kidneys and their ducts. The tail, which is about double the 

 length of the head and body, has been removed. X 22. 



A, dorsal aorta ; AFi, AF3, afferent branchial vessels of first and 

 thiid branchial arches ; AL, lingual artery ; CG, carotid gland ; EA, 

 junction between afferent and efferent branchial vessels of first 

 branchial arch ; EFi, EF3, efferent branchial vessels of first and third 

 branchial arches ; GM, glomerulus ; KA, archinephric or segmental 

 duct ; KM, Wolffian tubules ; KP, pronephros or head kidney ; 

 KSi, KS3, first and third nephrostomes of head kidney; LI, upper 

 lip ; LJ, lower Up ; LP, hind limb ; OA, aperture of opercular cavity; 

 OP, opercular cavity ; RS, sinus venosus ; RT, truncus arteriosus ; 

 RV, ventricle ; TC, cloaca ; TO, oesophagus, cut short ; TP rectal spout. 



