262 Mr. ALpERSON on a Whale of the Spermaceti Tribe. 
(+ inch in thickness), and was of great length, owing to the 
extraordinary breadth of the head at this part. The diameter 
of the mass, including the sheath, was about two inches at its 
insertion into the sclerotica, but gradually decreased as it ap- 
proached the bony canal in the frontal* bone, through which 
the nerve passes to the brain. 
The sole use of these muscles must be to draw in the eye. 
The optic nerve itself appeared to have a vascular tunic. 
The Heart.—This viscus was furnished with a pericardium, 
and in structure was exactly similar to that of man. It was 
very flaccid, and the parietes, when examined on the 9th of 
May, lay in contact. 
Its weight was 171\bs. 
The descending cava measured 9 inches in diametert: the 
ascending cava was not with the heart, for it was not examined 
in situf. 
Diameter of the pulmonary artery 122 inches; thickness of 
the coat +inch. 
Breadth of one of the semi-lunar valves of the, pulmonary 
artery, 5 inches; its length 17 inches. 
There was no corpus sesamoideum apparent. 
1 
The diameter of the aorta was 12 inches. 
Thickness of the coat of the artery 7 inch. 
* However misplaced the orbit, it is still the frontal bone which dips down to 
form it: the sutures are well marked in Fig. 1. Plate XIV. 
+ As these diameters were obtained through the medium of the half circumferences, 
it is probable, from the more yielding nature of the coats of veins, the measurements 
of the veins will rather exceed the truth, and those of the arteries rather fall short 
of it. 
} The heart was examined at the house of Mr. Sawyer, Surgeon, at Hedon, to 
whom I have to acknowledge myself indebted for his kind and skilful assistance in its 
examination. ik 
