234 THE SENSE-ORGANS AND PERCEPTION OF FISHES. 



buds " are found in clusters on the large papillae wliicli occur on 

 tlie gill-bars of tlie dog-fisb (as observed by Merkel), of Cottus, and 

 many other forms. The whole sense-organ may be placed on the 

 general surface of the skin, or it may be depressed into a pit or 

 elevated on a papilla, according to its situation and the animal in 

 question. 



The cells forming these sense-organs consist of a very long*, 

 narrow cylindrical head, which is external, an internal enlargement 

 in which the nucleus lies, and a tail passing into a fibre of varying 

 length [v. fig. 15). 



These sense-organs have a general resemblance to those of the 

 lateral line, but the cells of which they are made do not appear to 

 bear a hair on their peripheral buds, as those of the lateral line do. 



I have examined them in the following forms, and have found 

 them on the parts stated. 



Bream [Fagellus centrodontus). On the palate. 



Bullhead {Cottus scorjniis). On the palate and on the papillne of 

 the gill-bars. 



Gurnards {Trigia). On the palate and not on the fingers of the 

 pectoral fin. 



Pogge [Agon^is cata^hractus) . On the villiform tentacles beneatb 

 the head. 



Wrasses {Lahridx). On the palate as patches of minute sense- 

 organs surrounded by ridges of skin. 



Grey mullet {Mugil). On the palate and in great numbers upon 

 the fleshy thickenings in the pharynx ; also in rows upon the white 

 rugge which form the anterior borders of these thickenings. 



Pollack {Gadus pollacMus) . On the lips and palate (a few). 



Pouting (6r. hiscus). On the lips, palate, barbel, and pelvic fins 

 in great numbers. 



Whiting {G. merlangus) . On the lips and palate. 



Eocklings [Motella). On all the barbels, pelvic fins,^ and palate. 



Blenny [Blennius gattorugine) . No sense-organs were found on 

 the tree-shaped processes, which stand up from the anterior nostril 

 and from the orbit. As these are parts which might have been 

 expected to bear such organs, mention should be made of their 

 absence. 



Plaice [Pleuronectes platessa). On the palate. 



Dab {Pleuronedes limanda). No sense-organs were seen on the 

 palate. 



Sole {Solea vulgaris) . Contrary to the natural presumption, the 



* In tbe last number of this Journal I stated that the pelvic fins of the rockling bore 

 no organs of special sense. In specimens since prepared with gold chloride they are easy 



to see. 



