RETROSPECT AND CONCLUSIONS 163 



with its eyes and ears, nose and month, is the source of more than 

 two hundi'cd idioms. If a list of the idioms, rehiting to the eye, 

 ear and nose (as an olfactory organ and not a feature) is made 

 it A\ill be fomid that there are forty-tln-ee idioms related to the 

 e5'"e, twenty-two relating to the car, and nine relating to the nose, 

 so that roughly the relative importance of these three senses is 

 in man five — three — one. We cannot apply this test to a dog, 

 but ])robably the relative importance of these senses in a dog Mould 

 be smell, as indicated by its marvellous scent, then hearing and 

 lastly sight ; but we imagine the proportional significance of each 

 sense would not vary to the same extent, that would appear to 

 be the case with. man. As regards hearing in the dog, it is known 

 that it can be called by a Galton whistle when the note sounded 

 is beyond the range of human hearing, and it is usually held that 

 a dog is coloiu" blind. 



Contrary to general opinion the range of hearing in a fish, 

 such as the mimiOAv, is as wide as in man. and there is good reason 

 to believe that fish are not colom'-blind. 



Fortunately the brain of a fish is so constituted that their is no 

 difficulty in estimating the relative importance of the different 

 senses in the make-up of the brain, as we have already had occasion 

 to note, in describing the various lobes and their different sizes 

 in the four groups of the carp family. There will, therefore, be no 

 difficulty in coming to some definite conclusions as regards the 

 brain of the sole, and these are, as we have already indicated, ol- 

 factory, auditory and tactile, as shown by the size of the olfactory 

 central acoustic and somatic-sensory lobes : the facial lobe is 

 insignificant, as there are no taste-buds on the papillary area. 

 Why the gustatory system should be neghgible in the sole and 

 so important in other bottom feeding fish is difficult to explain, 

 and we have no answer available. 



The fact that the sole is able to live in brakish water makes it 

 seem probable that it may be in an early evolutionary stage towards 

 becoming anadromous, like the flounder. The sole likes warmth 

 and has been known to live in fresh water, and this accounts for 

 its occasional wanderings into estuaries. 



This raises the question of choice. Recently Professor F. 

 Balfour-BroMne gave an interesting Presidential Address on the 

 species problem in relation to water-beetles, and the conclusions 

 he drew may help us to understand the liistory of the sole. If 

 choice can be attributed to ^atcr-beetles, it can also be attributed 

 to flat-fishes, winch are far higher up the ladder of evolution. He 

 pointed out that although the struggle for existence undoubtedly 



