of the Fisher ji Board Jor Scotland. 275 



second epibranchial. The latter bone articulates also by means i»f its 

 wide upper extremity with a process of the second pharyngeal ossicle. 

 The first pharyngeal rests on an expanded thin portion of the second 

 pharyngeal, which is the largest of the three. Its toothed area is some- 

 what triangular in shape. From the ventral anterior edge the thin plate 

 of bone which supports the first pharyngeal projects. This expansion 

 shows three articular processes, of which the more anterior is the thinnest. 

 The latter process articulates, along with the first pharyngeal, with the 

 first epibranchial. The median articular process of the second pharyngeal 

 joins, as was mentioned above, the second epibranchial. The third 

 process, which is very broad, articulates v.'ith the third and fourth 

 epibranchials. 



The third pharyngeal is a little disc-shaped toothed area. It rests on 

 the large articular process of the second pharyngeal, and is bound by 

 ligaments to the superior ends of the third and fourth epibranchials. 



Loirer Pharyngeal (1. Phr.). 



Lythb, Fig. 2 Iff, Pi. IV. 



The lower pharyngeals are situated one on each side of the fauces : they 

 meet in the middle line beneath the opening of the oesophagus. Each 

 consists of a long narrow bone bearing a broad elliptically-shaped plate. 

 This plate, which is curved inwards, is covered with teeth. It does not 

 rest symmetrically on the bone, but projects out over the inner edge. 

 The anterior end of the pharyngeal is hollow and lodges a ligament which 

 serves to bind it to its fellow of the opposite side. 



Comparison between the Bbanohials of the threr species. 



The description of the branchial bones of the lythe holds good generally 

 for those of the saithe and cod. In the cod, however, the first cerato- 

 branchial is the shortest, the second and third are a little longer than the 

 first, and the fourth is the longest. In the saithe the first is the longest, 

 the second is next in length, and the third and fourth, which are of the 

 same length, are a little less than the second. 



Basibranchials (b. Br.). 



Cod, Fig. 20, PI. XI. : Saithe, Fig. 14, PI, XI. : Lythe, Fig. 7, PI. IV. 



The second basibranchial of the lythe is distinguished from those of 

 the cod and saithe by the fact that it has two small patches of teeth on 

 it, whereas in the two latter fishes no teeth are found on that bone. 



Hypohranchials (hp. Br.). 

 Cod, Fig. 21, PI. XI. : Saithe, Fig. 15, PL XI. : Lythe, Fig. 21, PI. IV. 



There are no very marked difierences between the first hypohranchials 

 of the three species. In the saithe the bone is more bent than in the 

 lythe. In the cod, however, the bone is not so much bent as i, ^,he lythe, 

 and the two arms are of equal length, whereas in the saithe and^lythe the 

 anterior is the shorter. 



In the second hypobranchial the three species are to be distinguished 

 by the form of the ventral surface of the bone. On the under or ventral 

 surface there is a groove which is continuous with the groove in the 



