of the Fishery Board for Scotland. 245 



The Eye : — The eye of the lythe is much larger than those of the cod 

 and saithe. In the two latter the eyes are of the same size, and the 

 horizontal diameter slightly exceeds the vertical diameter. In the lythe 

 the vertical diameter is a little larger than the horizontal. 



Interorhital Space : — Very few measurements of this character were 

 made, but these show a distinctly broader interorhital space in the cod 

 and saithe than in the lythe. 



Length of Snout : — AH three differ from one another in the length of 

 the snout. Shortest in the saithe, it is a little longer in the cod than in 

 the lythe. 



Projection of Mandible : — The mandible of the lythe projects in front 

 of the premaxilla on an average twice as far as it does in the saithe. 



Distances from the Tip of the Premaxilla. 



Ventral Fin : — The base of the ventral fin is in each form further 

 forward than that of the pectoral, and is also slightly in front of the 

 top of the opercular cleft. In the saithe the ventral fin is situated at 

 about the same level as in the lythe, and in both of these species it is 

 anterior to its position in the cod. 



Opercidar Cleft : — The opercular cleft occupies the same position in 

 the saithe and the lythe, considerably in front of its situation in the cod. 



Pectoral Fin : — A relation similar to that found in the case of the 

 opercular cleft, exists in res^ject to the position of the base of the pectoral 

 fin. In the saithe and lythe, in which they are at the same level, they 

 are in front of that of the cod. 



Amis : — In the position of the anus the three species differ from one 

 another. In the lythe the anus is furthest forward ; next comes the saithe, 

 aod behind it again the cod. The anus has in each a definite position 

 with respect to the first or second dorsal fin. In the lythe and saithe it is 

 below the first dorsal ; but while in the former it is perpendicularly below 

 the anterior half of the first dorsal fin, in the latter it lies below the 

 posterior half of the same. In the cod the anus is vertically below the 

 anterior half of the second dorsal fin. 



First Dorsal Fin : — The first dorsal fin begins further forward in the 

 cod than in the saithe, and in the latter it is in front of the same in the 

 lythe. As in all three species the first dorsal fin ends at about the same 

 level, their bases are correspondingly greater the further forward the fins 

 begin. Thus the bases of the first dorsals measure — cod, 13'4 ; saithe, 

 irS; lythe, 10-2 per cent, of the length of the fish respectively. 



Second Dorsal Fin : — The second dorsal in the cod and saithe begins 

 sooner than in the lythe. In the cod it ends first, next in the lythe, and 

 last in the saithe. The bases of the second dorsals measure — cod, 19"9 ; 

 saithe, 22-7 ; lythe, 19"7 per cent, of the length of the fish. 



Third Dorsal Fin .-—This fin commences earlier in the cod than in the 

 lythe, and in the latter a little in front of the level of its beginning in the 

 saithe. It ends in a corresponding order. In the saithe it comes con- 

 siderably further back than in the other two. The base of the fin 

 measures — cod, 13*9 ; saithe, 13*3 ; lythe, 12-2 per cent, of the length of 

 the fish. 



The length of the finless peduncle, that is, the interval between the 

 end of the third dorsal and the beginning of the dorsal edge of the tail 

 fin, is — cod, 2*5; saithe, 3'2 ; lythe, 3*5 per cent. In the lythe and 

 saithe it is longer than in the cod. 



First Anal Fin : — The same relative positions which were found in the 

 case of the anus, naturally hold good with respect to the beginning of the 



