ANATOMY OF THE TURTLE. 



509 



mesentery, and contains three oval eggs, one of which is 

 lettered Eg. The oviduct can be followed to its anterior- 

 end which is much pigmented and has a terminal opening. 

 The cut-end of the left oviduct (ovd) shows the folds of the 

 lining mucous membrane. 



The ovary (o) is likewise suspended by a thin membrane, 

 the mesovarium, and is equally developed on both sides in a 

 complete specimen. It is easily recognized by the numerous 

 bulging yellow spheres, of all sizes, which are the egg-yolks 

 in various stages of development. 



The heart of the turtle (Fig. 447) will repay careful dis- 

 section. A small round body lies just in front of it ; this is 

 usually considered the equivalent of the thyroid gland, 

 through its real nature is still un- 

 certain. The heart itself (Fig. 447) 

 consists of two auricles and one 

 ventricle (ven), with an imper- 

 fect internal septum. It receives 

 the veins upon its dorsal surface, 

 and gives off the arterial trunks 

 from its ventral side. The two 

 auricles are equal in size ; together 

 they a little more than equal the 

 ventricle. The arterial vessels arise 

 together a little to the right, and 

 are most conveniently described as 

 three in number : 1st. The right 

 aorta (R Ao) arising on the left ; 

 3d. The left aorta on the right Fig. 447. ventral surface of 



., . the heart of the Turtle, Cliryse- 

 (L Ao) the tWO CrOSS near their mys pitta. Dissected and drawn 



. . T i i i by C. S. Minot. 



origin and curve upwards and back- 

 wards, to reunite posteriorly just in front of the retractor 

 muscles, their union forming the single median descending 

 aorta ; 3d. The pulmonary aorta (p(t), which soon divides 

 into a branch for each lung. The left aorta gives off a 

 branch (d) which persists as a mere cord, the remnant of the 

 (/xrfus arteriosus, which originally united the aorta with the 

 pulmonary artery. The right aorta gives off an innominate 

 branch, that soon divides, and from each division springs 



