PROBLEMATICAL ORGANS OF SENSE. loi 



eminent jDhysicians and scientific men generally in this country or 

 in the world. I believe that such information would be of more 

 value to the world, after having been properly digested, than all 

 the facts about the manufacture of cotton cloth, the raising of 

 tobacco, the production of whisky, etc., that could be collected in 

 a century. For do we not all desire to live long ? 



PROBLEMATICAL ORGANS OF SENSE.* 



By Sib JOHN LUBBOCK. 



IN addition to the organs of which I have attempted in the pre- 

 ceding chapters to give some idea, and to those which from 

 their structure we may suppose to perform analogous functions, 

 there are others of considerable importance and complexity, which 

 are evidently organs of some sense, but the use and purpose of 

 which are still unknown. 



" It is almost impossible," says Gegenbaur,f " to say what is the 

 physiological duty of a number of organs, which are clearly sen- 

 sory, and are connected with the integument. These enlargements 

 are generally formed by ciliated regions to which a nerve passes, 

 and at which it often forms enlargements. It is doubtful what 

 part of the surrounding medium acts on these organs, and we 

 have to make a somewhat far-fetched analogy to be able to re- 

 gard them as olfactory organs." 



Among the structures of which the use is still quite uncertain 

 are the muciferous canals of fishes. The skin of fishes, indeed, 

 contains a whole series of organs of whose functions we know 

 little. As regards the muciferous canal, Schultze has suggested J 

 that it is a sense-organ adapted to receive vibrations of the water 

 with wave-lengths too great to be perceived as ordinary sounds. 

 Beard also leans to this same view. However this may be, it is 

 remarkably developed in many deep-sea fish. 



In some cases peculiar eye-like bodies are developed in con- 

 nection (though not exclusively so) with the muciferous canal. 

 Leuckart,* by whom they were discovered, at first considered 

 them to be accessory eyes, but subsequent researches led him to 

 modify this opinion, and to regard them as luminous organs. 



* From " The Senses, Instincts, and Intelligence of Animals," by Sir John Lubbock. 

 " International Scientific Series," vol. Ixiv, in press by D. Appleton & Co. 



f " Elements of Comparative Anatomy." 



X " Ueber die Sinnesorgane der Seitenlinie bei Fischen und Amphibien," " Arch, fiir mic. 

 Anat.," 18Y0. 



* "Deber muthmassliche Nebenaugen bei einem Fische." Bericht iiber die 39 Vers., 

 " Deutscher Naturforscher," Giessen, 1864. 



