of the Fisher i) Board for Scotland. 



Ill 



The abdominal cavity — the colour of the peritoneum ; the first 

 haemal arch ; the form of the abdominal cavity ; the shape 

 of the swim-bladder. 



The form of the urinary bladder. 



The position of the ureter with respect to the swim-bladder. 

 The shape of the ovary. 

 The pyloric caeca. 



The skeleton. Comparison between the skulls and certain bones 

 of the different species. 



KEY. 



In cases where measurements are adopted in the key, they are made on 

 similar lines to the measurements described on pages 98 and 99. A pair 

 of compasses will be suitable for this purpose. Distances are measured 

 along the lateral axis. 



In the key the aeglefinus from Scotland and Iceland are combined. 



I. Lower Jaw : — 



a. shorter than upper jaw callarias, ogac, aeglefinus, navaga, 



merlangus, luscus, minutus. 



b. of same length as upper jaw ..virens (sometimes in young). minutus 



(sometimes). 



c. projects in front of „ ,, virens, pollachius, poutassou, argen- 



teus, esmarki, saida. 



II. Anus : — 



a. in front of the first dorsal fin. ..poutassou. 



b. below the beginning of the 



first dorsal fin luscus. 



c. below the first half of the 



first dorsal fin luscus, pollachius, merlangus. 



d. about the middle of the first 



dorsal fin merlangus, minutus. 



e. below the second half of the 



first dorsal fin , minutus, virens, esmarki. 



/. below the end of the first 



dorsal fin aeglefinus, argenteus, saida, navaga. 



g. below the interval between the 



first and second dorsal fins... aeglefinus, argenteus, saida, callarias, 



ogac. 



h. below the first half of the 



second dorsal fin callarias, ogac, aeglefinus (in two 



specimens from Iceland the anus 

 was immediately below the be- 

 ginning of the second dorsal fin). 



III. Lateral Line : — 



a. straight, white virens (white not always prominent 



in small specimens). 

 „ „ indistinct poutassou. 



b. curved callarias, ogac, navaga, pollachius, 



minutus. 



,, „ slightly aeglefinus, merlangus, esmarki, argen- 

 teus, saida (see below). 

 , , curve double saida. 



c lateral line black (usually jet- 

 black) aeglefinus. 



