260 Part III. — Twentieth Annual Report 



process which runs up on the outer edge of the paroccipital. In the cod 

 this process is short, and it is a sort of angular cap fitting on the edge of 

 the paroccipital. The dorsal process of the paroccipital is pierced by a 

 foramen on the outer side of its base. By this foramen issues the nervus 

 lateralis (Owen). 



Ojnsfhofic (op. 0.). 

 Cod, Fig. 49, PI. IX. : Saithe, Fig. 14, PI. IX. : Lythe, Fig. 28, PI. IX. 



The opisthotic articulates with the prootic in front, the squamosal and 

 paroccipital above, the parasphenoid and basioccipital below, and the 

 exoccipital behind. 



In the saithe the process which articulates with the corner formed by 

 the paroccipital and the exoccipital bones is much longer than in the cod 

 and lythe. In the former it is more than half the length of the process 

 which articulates with the hind projecting portion of the squamosal ; 

 that is, measuring from the angle between the two processes of the 

 opisthotic. In the cod and lythe the process is very siuall. In the 

 saithe the long process which articulates with the squamosal is slender 

 and sharp-pointed : in the cod it is broad and ends in a blunt extremity ; 

 in the lythe it is broader towards the tip than in the saithe, but it some- 

 times ends in a sharp point. 



On the posterior edge of the base of the long process there is a roughened 

 area for articulation with the short arm of the post-temporal. 



Exoccipital (e. Oc). 

 Cod, Fig. 41, PI. IX.: Saithe, Fig. 5, PI. IX. : Lythe, Fig. 20, PI. IX. 



The exoccipital articulates above with the paroccipital, above and on 

 the inner side with the supraoccipital, on the outer side with the opisthotic, 

 and below with the basisphenoid. Behind, it is bound, liy means of a liga- 

 ment lodged in its hollow posterior process, to the atlas vertebra. 



The ridge running longitudinally on the bone is much more prominent 

 in the saithe than in the cod and lythe. 



On the internal surface of the bone projecting into the cranial cavity 

 there is a peculiar process, which consists of a broad hlade connected to 

 the main bone by a narrow neck. The blade is long, more than twice its 

 breadth, and tapers to a point in the saithe and lythe. In the cod it is 

 rather short and thick, in length not twice its breadth ; its free end is 

 broader than the rest of the process. The neck part is in the lythe very 

 narrow, in the saithe and cod it is much broader than in the former. 



Paroccipital (par. O.). 

 Cod, Fig. 40, PI. IX. : Saithe, Fig. 4, PI. IX. : Lythe, Fig. 19, PI. IX. 



The paroccipital is of an irregular hollow pyramid shape. It forms 

 the corner between the parietal, supraoccipital, exoccipital, squamosal, and 

 opisthotic. Its edge of attachment to the squamosal is smooth, without 

 sutures, the union being made by means of cartilage. The hind edge of 

 the disarticulated bone is always less than the superior edge. 



The paroccipital of the saithe is much larger than that of the cod and 

 lythe. In the lythe the greatest breadth of the base of the pyramid is 



