SENSES AND THE CENTRAL NERVOUS SYSTEM 23I 



in 1890 visiting a number of Norwegian whaling stations and collecting 

 specimens. In Tromsö, he met Svend Foyn, the inventor of the harpoon 

 gun and the owner of some of the stations, and discovered that Foyn 

 'dislikes scientists and cannot bear to have strangers visiting his whaling 

 stations'. Fortunately, other whaling masters proved less intractable, 

 particularly Capt. Bull on Sörvad station (near Hammerfest), who received 

 him most hospitably and entertained him for some weeks. Matthiessen 

 acknowledged his debt to his host and to other helpers in his subsequently 

 published paper, in which he showed, inter alia, that the cornea, the 

 aqueous humour and probably also the vitreous humour of the Cetacean 

 eye have the same refractive index as sea water. In other words, they do 

 not bend rays of light entering from the water, and the shape of the cornea 

 can have no influence on the path of the rays. The optical properties of 

 the eye are therefore primarily controlled by the lens. 



Because of adaptations to its aquatic environment, the Cetacean eye 

 necessarily functions less efficiently on the surface, where images will form 

 in front of the retina and consequently be blurred - the animals become 

 shortsighted and in need of concave glasses. Some authorities believe that 

 whales and dolphins cannot see anything at all out of the water, but 

 experiments in the Marineland aquaria (Florida and California) have 

 shown that this belief is erroneous, for, as we have seen, Bottlenose 

 Dolphins can catch fish in mid-air (Fig. 120), jump through hoops, pull 

 at a bell-rope, follow the movements of a hand some fifty feet away, and 

 recognize their keepers. In short, they behave in such a way that we must 

 conclude that their eyesight out of the water is fairly good, in fact remark- 

 ably good when we consider how well the same eyes enable them to see 

 below the surface. Dudok van Heel made similar observations with 

 porpoises, and Tomilin with Common Dolphins. Moreover, Killer 

 Whales are believed to scan the surface of the sea carefully, and even to 

 pounce upon seals lying on ice-floes, while Rorquals (and particularly 

 Little Piked Whales) have been observed to look up between cracks in the 

 ice (Figs. 222 and 223). The same behaviour has been reported of Grey 

 Whales also. 



In Odontocetes, visual acuity is undoubtedly due to lens accommoda- 

 tion, and their ciliary muscles are, in fact, well developed. Mysticetes, on 

 the other hand, seem to lack ciliary muscles, and their eyes can therefore 

 not be accommodated. Matthiessen has, however, inferred that while 

 Mysticetes cannot see clearly above water their retina can, nevertheless, 

 register impressions of moving objects and of outlines. Moreover, Fischer 

 (1946) believes that the shape of their eyes, and also those of Sperm 

 Whales, is such that the distance between lens and retina is greater in the 

 upper and smaller in the lower eye. Aerial images would then be focused 



