56 ANATOMY OF A CHELONIAN. 



on either side of the bladder aperture ; on these the 

 oviducts open ; pass a probe through one. If the ovi- 

 duct contains no ova it is often hard to find ; in that 

 case inflate it from its cloacal termination. 



142. Next make the dissections described in sections 

 133-137 inclusive ; reading, where necessary, "ovary," 

 for "testis and epididymis." 



143. Remove the heart very carefully, dividing the 

 vessels at some distance from it v?here practicable. 

 Place it on virax in a shallow dish containing dilute 

 alcohol ; fix it (by pins passed through the vessels) in 

 various positions as may be most convenient, and 

 carefully make out the points at which, as viewed from 

 the exterior, various vessels enter and leave it (94). 



144. Next cut away cautiously the ventral side of 

 the ventricle, and note the incomplete septum attached 

 to this wall and partially cutting off a small right por- 

 tion {cavum pulmonale) from a larger left division of the 

 ventricular cavity. Projecting into the left division is 

 the posterior free end of the auricular septum, which 

 thus incompletely divides the left portion of the ven- 

 tricle into a right half {cavum venosum) which gets blood 

 from the right auricle, and a left (cavum arteriosum) 

 which receives blood from the left auricle. 



145. Open the pulmonary artery and pass a bristle, 

 guarded at the end with a small knob of sealing-wax, 

 along it to the heart. Though the furthest left of the 

 vessels springing from the ventricle when the heart is 

 viewed from outside, the pulmonary artery will be 



