WITH THE WHALERS AT DURBAN. 



209 



deep from front to back. The sclerotic coat, in section, is thin 

 at its anterior margin, then it suddenly thickens to over an inch 

 through, and at its posterior part each side folds in to form the 

 passage for the optic nerve, which is small, leaving an open 

 space at the posterior part of the eyeball, filled in by a venous 

 plexus, or rete mirabile ; besides this there is a distinct channel 

 in the thick sclerotic, and circumscribing the eye, also filled in 

 with a venous plexus. What a superb specialization all this is 

 to resist the pressure of sea-water, especially when the animal 

 is going at speed in deep water ! The posterior chamber of the 

 eye is two inches across, and not more than two ounces capacity 



Cornea. 

 Lens. 



Anterior thin process of sclerotic. 

 Posterior chamber. 



Sclerotic coat. 



Sheath of optic nerve. 

 Channel in sclerotic coat. 



Posterior process of sclerotic. 

 Ketia mirabilia. 



Section of the eye of Humpback Whale (Megaptera buops), to show the great 

 thickness of sclerotic coat ; the space at its posterior part and the channels 

 in it filled with retia mirabilia. 



The only evidence of an ear in the outer part of the body is 

 a small longitudinal slit, half an inch long and about sixteen 

 inches behind and below the eye ; but when one cuts into this, 

 what a revelation ! It is found that the external auditory 

 meatus passes through a dense mass of yellow fibro cartilage, a 

 foot or so in thickness, from side to side, which seems to indicate 

 that the Whale's ancestors may have had external pinnae, but 

 that, like the bind limbs, they were found to be in the way ; so 

 they have become tucked away under the skin ! 



The notes of the internal organs following were only made in a 

 perfunctory manner, as the body was being torn and hacked and 



