456 FISHES OF THE FIRTH OF FORTH. 



DR PARNELL'S ARRANGEMENT OF THE FISHES OF THE 

 FIRTH OF FORTH, which, by a simple analysis of charac- 

 ter, facilitates the Naming- of the diflPerent Species : — for ex- 

 ample, the Lamprey (Petromyzon) having seven branchial open- 

 ings on each side, is referred from Division 1. to Division 64, 

 vmder which number the reader finds it distinguished from Am- 

 mocoetes by the presence of teeth. 



Division. Page, 



iOne branchial opening on each side* > 2 

 Five branchial openings on each sidef 56 

 Seven branchial openings on each sidej 64 



(Ventral fins wanting 3 

 Ventral fins jn-esent 9 



( Dorsal and caudal fins contiguous 4 



\ Dorsal and caudal fins sej^arate: 6 



f Body very much elongated, eel shaped 5 



' (Body oval, truncated behind Orthagorisciis. 401 



; Under jaw longest AnguiUa. 384 

 Under jaw shortest Conger. 388 



• The branchial or gill-opening is in general a large aperture situated on 

 each side of the neck, and covered by a thin osseous plate or gill-cover, 

 as in the Herring (Clupea), Trout (Salmo), &c. ; sometimes we find it re- 

 duced to a small orifice on eachside of the nape, as in the Pipe-Fish 

 (Syngnathus), DragoJiet (Callionymus), &c. ; occasionally it is an open- 

 ing above the base of the pectorals, as in the Sun-Fish (Orthagoriscus) ; 

 sometimes, as in the Eel (Anguilla), it is an opening of an oval form in 

 front of the lower part of the base of pectorals ; at other times again it is 

 in the form of a large opening concealed behind the pectorals, as in the 

 Angler (Lophius). 



■f These openings are either placed along each side of the neck, as in the 

 Shark (Squalus), or on the under surface of the body as in the Skate (Raia). 



t These are always in a longitudinal series on each side of the neck, as 

 in the Lamprey (Petromyzon). 



