The caecilian cardio‐vascular system and intra‐amphibian relationships

Abstract

The cardio‐vascular system of Hypogeophis is described and compared with that of other caecilians. The extant caecilians are divisible into two geographical groups in which the varying degrees of asymmetry of the arterial arches evolved in parallel. The nomenclature of the cephalic veins is discussed and the cranial circulation of caecilians is compared with that of some urodeles and anurans. The general similarities which exist between the vascular system of caecilians and urodeles may be indicative of a close relationship. However, it is pointed out that more detailed information is required before intra‐amphibian relationships can be established with any degree of certainty.