Brooks — The Osteology and Arthrologtj of the Haddock. 177 



larger teeth are in the outer series. On the mandible they are 

 not so numerous, and are more uniform in size. The dentary 

 bends inwards in front to join its fellow of the opposite side. The 

 dentigerous edge is continued upwards and backwards into a 

 process, which nearly touches the upper angle of the articular, to 

 which it is bound by ligamentous fibres. A strong ridge runs 

 from before backwards along the middle of the bone, and is 

 connected to the dentigerous border externally by a thin osseous 

 lamella, and internally by a somewhat similar lamella, which, 

 however, extends farther backwards. Into the space between 

 these two scales of bone the articular, with Meckel's cartilage, fits. 



The angular is a small, irregular nodule of bone, which unites 

 by suture with the articular in the manner above-mentioned. A 

 strong ligament connects its posterior border with the interoper- 

 culum. 



The nasal (PI. YII., fig. 14) is a scale of bone, curved in such a 

 manner as to produce a gutter-like depression on its upper surface, 

 running from before backwards. This is filled with mucous glan- 

 dular tissue in the recent state. Its internal edge touches its fellow 

 in front. Behind, for a short distance, it is in contact with the 

 ethmoid. The external edge touches the lachrymal, and the ante- 

 rior end overlies the maxilla and premaxilla. To all these bones, 

 and also to the pre-ethmoid cartilage, it is connected by liga- 

 mentous fibres. 



The lachrymal (PL YI., fig. 4, 4) presents above a stout ridge, 

 which runs parallel to the outer border of the nasal. This splits 

 below into two laminae, of which the external extends the lower 

 down. Its posterior superior angle articulates with the prefrontal. 



The suborbitals are five small bones built on the type of the 

 lachrymal; namely, a ridge next the orbit splitting peripherally 

 into two laminae. 



The preoperculum (PL VI., fig. 5, s) is another bone of this type, 

 the ridge being in front, curved, with the concavity forwards. The 

 internal lamina (as in the lachrymal and s]iborbitals) is the larger, 

 and it extends farther backwards than the external. The ridge 

 articulates with the quadrate below, and is overlapped by the 

 middle process of the hyomandibular above. From the middle of 

 the concavity a scale of bone extends upwards and forwards, and 

 is wedged between the anterior and middle processes of the hyo- 



