KA 



KM 



LP 



TB 



FlG. 24. A I2-MM. TADPOLE DISSECTED FROM THE VENTRAL 

 SURFACE TO SHOW THE HEART, THE INTERNAL GILLS, THE BRAN- 

 CHIAL 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. (After Marshall.) 



A, dorsal aorta. A F.\, A ^.3, afferent branchial vessels of first and th'rl 

 branchial arches. A , lingual artery. C(7, carotid gland. EA, junction be. 

 tween afferent and efferent branchial vessels of first branchial arch. E F.\, L A3, 

 efferent branchial vessels of first and third branchial arches. GM, glomerulus. 

 KA) archinephric or segmental du^t. KM, Wolffian tubules. K P, prone- 

 phros or head-kidney. K .S'.l, A'^T.3, first and third nephrostomesof head-kidney - 

 L /, upper lip. LJ, lower lip. L P, hind limb. O A , aperture of opercular 

 cavity. O^P, opercular cavity. R S, sinus venosus. R 1\ truncus arteriosus. 

 R V) ventricle. TC, cloaca. TO, oesophagus, cut short. T R, rectal spout. 



66 



