of the Fishery Board for Scotland. 



109 



In the next table are shown the ranges of variation in the numbers of 

 vertebrae and fin-rays that have been found during this research. The 

 particulars, with the numbers of variants, have been already shown in 

 this and the two previous papers. This table may be used for the specific 

 discrimination by means of the fin-rays. 



Number of Vertebrae and Fin-rays. 

 Range of Variation. 



* The data furnished for this species by Vanhbffen and Smitt have been included, 

 f The data furnished by Kolreuter and Smitt for this species have been included. 

 X The data furnished for this species by Giinther, Vanhbffen, Smitt, and Jensen have been 

 included. 



It is not necessary to discuss the external characters individually, 

 although it may be well to append notes on certain of them. The results 

 of my enquiry into the varied relationship are set out in the key. The 

 intention has been to express the characters on broad lines. Very 

 accurate measurements cannot be adopted in a diagnosis, owing to the fish 

 being liable to damage or distortion. Distortion or injury may render 

 some of the test-characters inapplicable. 



Girth. — The girth is of considerable importance as indicating the shape 

 of the fish. It is, however, a character that should be measured on 

 fishes in good condition. Where preserved fishes are used only 

 approximate values can be got, and even in fresh material the soft tissues 

 may yield more in one specimen than in another. It would be an 

 advantage to have some characters which would give a definition of the 

 body of the fish, since each species has a general form distinctly different 

 from its neighbours. In this connection a comparison between the 

 species in the dorsal aspect would be of value. 



Th Spacb between the Second and Third Dorsal Fins. — The 

 wide gap on the dorsal edge between the second and third dorsal fins 

 is a prominent character in poutassou. It is a character that varies 



