Fig. 23. A. — Diagrammatic figure of the head and ante- 

 rior PART OF THE BODY OF A 7-MM. TADPOLE, SHORTLY AFTER 

 HATCHING ; SHOWING THE BRANCHIAL BLOOD VESSELS FROM THE 

 VENTRAL SURFACE. ThE HEART HAS BEEN REMOVED. 



B. — Same embryo, from the right side. The heart is rep- 

 resented IN situ, but the external gills of the first and 



SECOND BRANCHIAL ARCHES HAVE BEEN CUT OFF SHORT AT THEIR 



BASES. (After Marshall.) 



A, dorsal aosta. A B, basilar artery. A C, carotid artery. A F.i^ A F.2, 

 A /^.3, afferent branchial vessels of the first, second, and third branchial arches. 

 A P, pulmonary artery. A 7?, anterior cerebral artery. A T, anterior palatine 

 artery. CA, anterior commissural vessel. CP, posterior commissural vessel. 

 £ F.l, EP^y E P.'A^ EFAy efferent branchial vessels of the first, second, third, 

 and fourth branchial arches. E H^ efferent vessel of hyoid arch. E M^ efferent 

 vessel of mandibular arch. GEy external gills. G^\ glomerulus, K A^ seg- 

 mental duct. KPy head-kidney or pronephros. KSA^ KS^^^ first and third 

 nephrostomes of head-kidney. L VA^ efferent lacunar vessel of fourth branchial 

 arch. RAy auricle. RV^ ventricle. R /*, truncus arteriosus. V D^ Cuvierian 

 vein. V Hy hepatic veins. KA", vein of sucker. VM^ mandibular vein. KK, 

 byoidean vein. 



65 



