THE HEART IN SAUROPSIDA. 



265 



kwo, a left and a right, at the time of the auricular systole. 

 The left portion becomes filled with arterial blood from the 

 left auricle, and is distinguished as the cavum arteriosum • 

 the right receives the venous blood from the right auricle, and 

 is the cavum venosum. 



No arterial trunk arises from the cavum arteriosum, but 

 two arterial trunks arise from the right-hand end of the cavum 

 vetiosum / these are the two aortic arches. One of these 

 passes to the left and the other to the right side, and thev 



A. 



'^r, 92.— Tlie Heart of a Turtle {Qlielone midas). — -4, a drawing from nature: the ventraJ 

 face of the ventricle being laid open. B, a diagram explanatory of the arrangement of 

 the cavities and vessels. 2i. A., L. ^., right and left auricles, w, a;, arrows placed In 

 the auriculo-ventricular apertures to indicate the course of the blood at the auricular 

 systole. ?j, the right, and 1)^, the left median auriculo-ventricular valves. C. ?).. cafinm 

 verbOHum. C. p., cavwm- pulmonale, a, the incomplete septum which divides the 

 cavum pulmonale from the rest of the cavity of the ventricle. P. A,, pulmonary artery. 

 E, Ao.^ Z. Ao.^ right and left aortic, s, arrow showing the course of the blootl in thfl 

 left aorta; t, in the right aorta; s, in the pulmonary artery; ?/, between the camtvi 

 venosum and camtm pulmonale ; £C,in the left, and w,ia the right auricalo-ventriculju 

 aperture. 



12 



