862 The American Naturalist. [October, 
the collapsed condition of the right as compared with the left 
side. The ventricle if it has rotated must have passed along 
the ventral aspect of the left auricle. . 
After a careful and completer dissection of the heart and the 
vessels adjacent to it so that the parts could be more easily 
manipulated, it was found that the ventricle could be returned 
to an approximately normal position which assisted quite 
materially in elucidating the relationship of the vessels to the 
heart and to each other. 
The two aortas at their diverging point are twisted half 
around each other, the right in this case being smaller than 
the left and sending off only one branch—the cervical artery ; 
the right aorta then passes dorsad of the trachea and cesopha- 
gus in an oblique caudal direction until it meets the left to 
form the common aorta. 
The left aorta presents a peculiar enlargement shortly after 
emerging from its “ twist, " due perhaps to over-distention with 
coagulated blood, and at the point of the greatest convexity of 
its eurve 1t sends off the carotid artery and gradually diminishes 
in calibre until it meets its fellow. It would appear from this 
that the left aorta, instead of being a mere connecting branch 
as is usually the case, has assumed the chief function of the 
right, supplying the head with blood through the carotid. 
The two aortas retain their crossed origins at the ventricle as 
in normal specimens. It is not improbable that the right 
aorta suffers more by the twisting than does the left, causing a 
greater retardation of the flow of blood and thus offering a 
possible explanation for its diminished size and partial loss of 
function. 
The right jugular vein was A enlarged near the 
heart but empty and was partially compressed by the ventri- 
cle. At about the level of the auriculo-ventricular furrow it 
receives the (pre?) azygous vein and the common venous 
trunk, which is of smaller calibre than the jugular, then fol- 
lows the dorsal contour of the right auricle, arching over to 
enter the sinus venosus at about the point of entrance of the 
postcava. 
The position of the sinus which normally is perhaps more 
