228 PROFESSOR TURNER'S ACCOUNT OF THE GREAT FINNER WHALE 



A well-defined tricuspid valve was placed at the right auriculo ventricular 

 orifice. The cusps had the same relative position as in the human heart, and 

 the arrangement of the carneae columnar, musculi papillares, and chordae ten- 

 dineae was closely similar. In the older whale one of the cusps measured 10 

 inches in width at its base, and the depth from base to apex was 8^ inches. 

 Some of the chordae tendineae were 12 inches long, and the girth of one of the 

 largest of these, where it arose from a papillary muscle, was 2^ inches. As it 

 subdivided before it joined the cusp, the size of its branches was very ma- 

 terially smaller. 



The pulmonary artery arose from a distinct conus arteriosus. It ran for- 

 wards and to the left, and divided into two branches for the right and left 

 lungs. Its left branch gave origin in the foetus to a widely patent ductus 

 arteriosus, which joined the arch of the aorta immediately behind a spot oppo- 

 site the origin of the left subclavian artery (Plate VII., x). 



In the mother a strong, fibrous, rounded cord, 5 inches long, passed between 

 the pulmonary artery and aorta in the place of the ductus arteriosus. Its 

 circumference at its aortic attachment was about 6 inches, and it was some- 

 what thicker at its opposite extremity. When transversely divided it was seen 

 to be distinctly laminated, and extending along its axis was a canal readily 

 admitting a large sized catheter. This canal widened out into a funnel-shaped 

 passage at its two extremities, where it opened into the aorta and pulmonary 

 arteries. Hence, even in the adolescent animal the arterial duct was patent, 

 though, from the small size of the canal, any intermixture of blood which might 

 have occurred would be so small as not to affect the characters of the enormous 

 volume of that fluid contained in the arterial system. It is interesting also to 

 note that Knox found a pervious ductus arteriosus in the great Rorqual which 

 he examined, and Dr Murie observed it in an adult Balcenoptera musculus* 

 The trunk of the pulmonary artery in the mother was 3 feet 7 inches in internal 

 circumference, and its coat, which was distinctly laminated, varied in thickness 

 from 1^ inch to fths of an inch. The internal circumference of one of the 

 primary branches was 1 foot 5 inches, the thickness of its coat -|th of an inch. 

 The internal circumference of one of the pulmonary veins was 19 inches. 



The left auricle, in the mother, had much thicker walls and a redder 

 colour than the right ; but in both, the appendages were large, and the fleshy 

 columns within them, and on the adjacent part of the auricular wall, were enor- 

 mously developed, one of the largest measuring 5 inches by 3, another 6 inches 

 by 2, and so on. The pouch-like dilatations, already referred to in the descrip- 

 tion of the foetal auricle, between these columns readily admitted one or both 

 fists. From the mode in which the columns intersected each other, they and 

 the pouches gave to this part of the auricle quite a cavernous character. The 



* Proc. Zool. Soc, Feb. 14, 1865. 



