of the Fit<heri/ Board for Scotland. 247 



Day* gives 51 as the number of the vertebrse of the cod. In the 

 "Scandinavian Fishes" the number is stated at 51-54 for the cod, 

 54-55 for the saithe, and 53, 54 for the lythe. According to Jordan and 

 Evermann,t the saithe has 54 vertebroe. 



Fin-rays. 

 (Table, page 241.) 



\st Dorsal: — The cod and the saithe have practically the same number of 

 rays in the first dorsal fin, viz., averages of 13'9 and 13 '8 respectively, 

 while the lythe has an average of 12 '8 rays. 



'2nd Dorsal : — In respect to this fin the cod and lythe approach one 

 another closely, having averages of 18'9 and 19'1 respectively, while that 

 of the saithe is 21*4 rays. 



3rd Dorsal : — Cod and lythe again resemble one another with respec- 

 tive averages of 18-8 and 18'1, while in the saithe the average is found 

 to be 21 -1 rays. 



1st Anal :—lu their average number of rays the saithe and lythe, with 

 27 '1 and 29 '7 respectively, are more nearly related to one another than 

 to the cod, in which there was an average of 21 -6 rays only. 



2nd Anal : — In the cod and lythe the averages are 17'8 and 189 

 respectively, while that of the saithe is 21*7 rays. 



It has been shown above that in certain characters two of the forms 

 approach each other closely, while they are separated by an interval from 

 the third species. Saithe and lythe resemble one another in the greatest 

 number of characters, but there are, however, certain dimensions in which 

 each of them is more nearly related to the cod than they are to one 

 another. 



The inter-relationships are set out in the following scheme. The first 

 two forms are in each case the closely-allied species, and the characters in 

 which they exceed, and those in which they are less than, the third form 

 are given in detail : — 



f Girth (at Anus) : D.-V. Height (at 



I Anus) : Projection of Mandible : d. 



> Cod -<^ (distance) of beginning of 3 D. : Fin- 



I rays (1 A.): I. (length) of base of 



Saithe and Lythe, ■( ^• 



ri., Ventral Fin : Greatest height of all 

 ^, , J Unpaired Fins : d., Ventral Fin : 

 ] d., Opercular Cleft : d., Pectoral 

 ^ ^ Fin : I. of base of 1 D. 



r ^ Q -fK f Glii'th (Pect.) : I., Pectoral Fin : d., 

 I ^ ^^"-^^^^ \ end of 1 D. 



Cod and Lythe, -^ . ^ ^ ^^^ ^^ 2 D. : d., end of 3 D. : d., 



< Saithe,^ beginning and end, 2 A. : Fin-rays, 

 t 2 D., 3 D., 2 A. : l, base, 2 D. 



r_ T i.1 r Interorbital space: I., base of 3D.: 

 I > Lythe, I j,i^.,^^y3^ 1 \)_ 



Cod and Saithe, -<( 



I T ^i, [ C^irth (at Tail) : Height of Tail : 

 ^< Lythe, I Di Jeter of Eye. 



* "The Fishes of Great Britain and Ireland," London, 1880-1884. 

 t "The Fishes of North and Middle America," Pt. iii., B}dl. U.S. Nat. Museum, 

 Washington, 1898. 



