Neurohemal organs in Myriapoda and phylogeny

Comparisons of neurohemal organs in Insecta and Myriapoda are made. The structure of the corpora cardiaca, the paraesophageal bodies and the blood sinus formations are paralleled. Some Diplopoda possess three protocerebral systems, among which the paraesophageal bodies – blood sinus formations system and the basic myriapodan lateral one. Diplopod paraesophageal bodies and blood sinus formations are reminiscent of the insect “aortal complex” system. Chaudonneret’s idea of two primitive lateral cords inherited from an annelid ancestor is adopted. His homology of corpora cardiaca and paraesophageal bodies is defended. The present study supports the view that Myriapoda and Hexapoda have a common ancestor.