The Morphology of Cosmobia 



385 



blood-vessels are somewhat abnormal in their relations, and may be made 

 out by the comparison of Figs. 10-13. Each ventricle possesses an 

 aortic arch, both of which pass to the ventral aspect of the vertebral 

 coliinm of component B, where they meet an arch from the right ventricle 



B 



Art. Pulm. to Rt. Lung of A. 

 Ant. Vena Cava 



To Aorta of B. 

 ■from Lft. Ventr 



To Aorta of B.- 

 from Rt. Ve 



A 



.Pulm. Vein from 

 '' Right Lung of A. 



Pulm. Vein from 

 Left Lung of B. 



Post. Vena Cava 



— /. Right Ventricle A. 



Fig. 11. Baldwin Syiiote, Teras III. Heart of perfect side; inner aspect. 

 Tlie dotted line across the auricular region marks the position of the incom- 

 plete partition separating the two auricles. The lungs and trachea have been 

 removed. 



Left Ventricle; 

 B. 



Right Ventricle 

 A. 



Fig. 12. Baldwin Syiiote, Teras III. Heart of perfect side; inner aspect, 

 c-ut open to show the interior chambers. The auric-ulo-ventricular openings 

 are marked by arrows. 



of the heart of the synotic side and together form B's dorsal aorta. 

 Since, in Cosmobia belonging to this series, the dorsal aorta of each 

 component is usually made up of the union of two arches, one from each 

 of the ventricles that belonged originally to the side in ques^tion, the 

 only departure from the type lies in the fact that the arch that arises 



