No. 472] ANATOMY OF CRYPTOBRANCHUS 



321 



The inferior cava enters the Hver near the apex of the right lobe. 

 By carefully dissecting away the substance of the liver, the course 

 of this large vein may be followed entirely through that organ. It 

 extends in a nearly straight line through the dorso-lateral part of 

 the right lobe, and emerges from the anterior surface of the liver 

 as the large thin-walled vessel that empties into the heart. Just 

 before, or at about the time of its emergence from tlie liver, it is 

 joined by the large hepatic vein, so that that i)ar( of tlic inferior 

 vena cava which is anterior to the liver is many rimc^ as larnc as 

 that part which is posterior to the liver. This coinpletes the de- 

 scription of the more important peripheral vessels of the vascular 

 system; and it now remains to describe the structure of the heart. 



The Heart 



The heart lies far forward in the body, just anterior to a line 

 joining the front legs. It is protected ventrally by the broad 

 underlying cartilages of the procoracoids and the sternum, to 

 which it lies so close that they must be removed with some care in 

 order not to cut into the pericardial cavity. The size of the heart 

 is moderate in relation to the size of the entire animal, and seems 

 to vary coiisidciaMy. even in animals of the same approximate 

 size. It has the vitality usually seen in cold-blooded animals, 

 and will continiic to beat for a considerable time after being re- 

 niovtMl from th<' body, or after being filled with the injection fluid. 



Kxtrrnal . I - When seen from the ventral aspect (Fig. 

 14, A), it |)rest>nts'six main region.s: tlie eoims arteriosus, the 

 Ixilbii. anerioMis, the ventricle, the right and left atria or a.irides, 

 Mtul the sinus venosus. These regions may be M^en from the dorsal 

 asi)e(t as well, if the heart be dissected from the ho.ly (Fig. 14, 

 W), jmd they will now be described in turn. Their form and rela- 



sion at the time they are sketched. The lieart from which the 

 figure was made, was moderately well filled with the injection 

 fluid, and differs considerably in general appearance from Osawa's 

 figures of the lieart of the Japanese salamander. 



The bulbus arteriosus (5.), to begin at the most anterior region 

 of the heart, is a striking object, seen on removing the skin and the 



