STRANDED AT LONGNTDDRY. 227 



I can say nothing more of the anatomy of the liver than that it was subdivided 

 into two lobes. The pancreas was not recognised in the course of the dissection. 



Organs of Circulation. — My observations on the arrangement of the heart and 

 blood-vessels were made chiefly on the foetus, but in several points were supple- 

 mented by a reference to the corresponding structures in the adolescent animal. 

 The heart was contained in a well-formed pericardium. In the mother it was of 

 enormous size ; and in the foetus it was considerably larger than the heart of an ox. 

 It presented externally the usual arrangement of grooves, which marked its sub- 

 division into four chambers, and in these grooves the coronary vessels ramified. 



In the foetus the right auricle, when opened into, showed a smooth inner 

 surface for the most part, but the anterior wall and the interior of the appendix 

 had well-defined fleshy columns projecting into the cavity. In the intervals 

 between these columns the auricular wall was dilated, and formed a number of 

 pouch-like recesses. The superior cava, large enough to admit five extended 

 digits, opened into the anterior and external part of the cavity, and had no 

 valve at the orifice. The inferior cava, large enough to admit the fist, opened 

 into the posterior and external part of the auricle. No trace of an Eustachian 

 valve was seen at its mouth. The mouth of the coronary sinus readily admitted 

 the tips of three fingers, and opened between the inferior cava and the auriculo- 

 ventricular orifice, and was also without a valve. 



In the interauricular septum an almost circular foramen readily admitting 

 five extended digits was situated. Surrounding this opening, and attached to 

 its edge, a loose, membranous, annular fold, formed by a duplication of the 

 endocardium was seen. When put on the stretch it projected into the auricle, 

 and the projecting border was free and pierced with large fenestras Although 

 this fold was situated in the right auricle, when I opened into that cavity, yet 

 it could without difficulty be passed through the foramen into the left auricle. 

 At the attached border, again, the membrane was almost entire, and most per- 

 fect in its anterior, external, and posterior portions, where the depth from the 

 attached to the free borders was 4 inches. This membranous fold was situated 

 at some distance from the mouth of the inferior cava, so that it could not be 

 regarded as the Eustachian valve in the sense in which it is customary to use 

 that term. From its position it would, however, seem to have served some pur- 

 pose in connection with the flow of blood from one auricle to the other during 

 foetal life ; but it is possible that, by growth both in thickness and surface, it 

 might, after the birth of the creature, have closed up the orifice and completed 

 the auricular septum. I think it probable that the structure described by Dr 

 Knox [Catalogue, p. 24), in the heart of a foetal mysticetus, as " a membranous 

 sac, the size of a full-sized thimble, presenting at the bottom a delicate reticu- 

 lated net-work, and projecting into the left auricle," was similar to the annular 

 fold observed in this foetal Balwnoptera. 



