Brooks — The Osteology and Arthrology of the Haddock. 175 



The pre-etlimoid cartilage is of a nodular form, slightly 

 flattened from side to side, convex above, the convexity being 

 interrupted by a groove behind, where the palato-premaxillary 

 ligaments cross it. The premaxillse and maxillse articulate with 

 its front and sides. Posteriorly it presents a deep groove, which 

 slides on the sharp anterior edge of the ethmoid. Above it is 

 overlapped by the nasal bones. It is connected to the maxillse 

 and premaxillse by* ligaments, and by weak ligamentous fibres to 

 the nasals and ethmoid. 



The premaxilla (PL VIL, fig. 9] is a small, curved bone, bearing 

 teeth on its lower surface. Superiorly, it presents two processes ; 

 and inferiorly, one. The anterior superior process presents a groove 

 (PL YIL, fig. 9, 4) on its inner surface, which affords attachment 

 to a ligamentous substance, connecting it to its fellow of the oppo- 

 site side. Just behind this (2) it articulates with the pre-ethmoid 

 cartilage, and, behind the articulation (3), a ligament connects it 

 with the cartilage. From the apex (1) passes a strong ligament 

 to the palate bone of the opposite side. The posterior superior 

 process presents postero-internally a little condyle (5), which arti- 

 culates with the maxilla, a bi-concave disk of fibro- cartilage being 

 interposed. The inferior process (7) slides on the inner side of 

 the maxilla, and keeps the premaxilla from displacement outwards, 

 especially when the mouth is closed. From the inner side of the 

 upper end (6) a ligament passes backwards to the maxilla, and 

 from the lower end a weak ligament passes to join the anterior 

 maxillo-mandibular ligament. 



The maxilla (PL YIL, fig. 10) is a rather slender, slightly curved 

 bone, flattened {i.e. compressed from side to side) below, the upper 

 end presenting posteriorly a convex articular head (fig. 10, 4), and 

 anteriorly two processes — an external and an internal. The head 

 articulates with a deep pit, formed by the ethmoid and vomer and 

 the cartilage between them, an interarticular fibro-cartilage being 

 interposed. The internal process gives attachment to a ligament 

 (2) going to the pre-ethmoid cartilage. Anteriorly it articulates 

 with the premaxilla (6), and gives attachment to the premaxillo- 

 maxillary ligament (1), and just below this presents a little spur 



s'opere le mouvement de la m&choire," and Meckel (Anatomie Comparee, French 

 edition, vol. ii., page 600) calls it " un cartilage articulaire, triangulaire." 



