OCCASIONAL NOTES. 191 



excellent plumage, is now in the hands of Mr. W. H. Vingoe, of Penzance, 

 for preservation. — Thomas Coknish (Penzance). 



Blindness in the Codfish. — Fishes, as a rule, are provided with two 

 eyes, symmetrically placed one on either side of the head, while they are 

 undoubtedly large as compared with what obtains in other vertebrates, or 

 even in comparison with the extent of surface in their own bodies. Their 

 size, however, is modified in accordance with local surroundings and their 

 habits. Some frequent muddy waters, where vision would be of less service 

 thau tactile organs ; in such cases appendages for feeling, as barbels, are 

 more developed than eyes. Others again are restricted to living in dark 

 caves where rays of light can hardly enter. Irrespective of the foregoing 

 cause of atrophy there are many forms residing in the dismal abysses of the 

 ocean where light is unable to penetrate, for solar rays are computed to be 

 lost at a depth of two hundred fathoms or less; while in the fresh waters of 

 the Lake of Geneva, Prof. Forel ascertained that at thirty fathoms photo- 

 graphic paper was entirely unacted upon. Another modifying influence is 

 whether the habits of the fish are nocturnal or diurnal, the former, unless 

 residing in dark places, requiring the larger organs of vision. Active 

 animals residing in the light are provided with eyes, while those having 

 limited powers of progression and residents in the dark are usually more or 

 less deficient in these organs. They may consequently be present in almost 

 the lowest animal forms, and absolutely wanting in some of the higher, as 

 the Shrew Mouse and the Mole. Eyes likewise may be only rudimentally 

 developed, as in the Amphioxus or Myxine, wherein they appear as mere 

 dark specks, but still have a nerve distributed to them. Or they may have 

 retrograded to so considerable an extent as to be entirely absent in some 

 forms which have taken up their abodes in dark caverns, but even here the 

 lens and other constituent portions of the eye may usually be detected, 

 whereas examples of the same species living outside are provided with fully 

 formed eyes. When we commence investigating the relationship which 

 exists in fishes' eyes to the localities they reside in or their general habits, 

 we must be struck by the fact that some forms live where the rays of solar 

 light are absent, others in the glare of the sunshine. But I do not purpose 

 entering in detail into the organs of vision of fish and their numerous 

 modifications, but to restrict myself to whether light can have such a modifying 

 influence on the eye of the Codfish as to occasion morbid symptoms and 

 even total blindness. In the thirteenth volume of the ' New Sporting 

 Review ' exists a most interesting account of a visit to Colonel McDowell's 

 vivarium for Codfish in the Mull of Galloway. An excavation was formed 

 in the rock about fifty feet in diameter, and at low tide about eight feet of 

 water remained in this basin, and six feet more at high tide. It was 



