ADAMS: SKULL OF THE WOLF-EEL. 353 



which extends from top to bottom, cutting off a part of the ar- 

 ticulating surface. The bone is depressed dorsally to the teeth 

 and also on each side of the posterior projection. 



Articulations. 



It articulates with the other premaxilla on the median line; 

 with the ethmoid, its dorsal posterior edge fitting into a con- 

 cavity on the anterior face of the ethmoid ; posteriorly with the 

 maxilla, the condyle of the maxilla fitting into a facet on the 

 premaxilla. 



Mandible. (Plate XXV, Man.; plate XXXVI, figs. 61, 62, 63.) 



The mandibles, in this family, are well built, and are differ- 

 ent from most fish jaws. The two rami are joined by a weak 

 suture, and are held by tissue. The two rami are at an angle 

 of about 45 degrees to each other. The symphyseal surface 

 is rectangular in shape, slightly narrowed at the ventral bor- 

 der. The ventral edge of the mandible is the base of the den- 

 tary, and is straight, except at a point near the chin, where it 

 curves slightly ventrally. The anterior edge is gently concave, 

 and also the dorsal border. The dorsal border is the tooth- 

 bearing surface. It is raised up to make a place for the teeth. 

 Posterior to the teeth the mandible is elevated dorsally and 

 ends in the coronoid process. The posterior edge is cut off 

 obliquely at the expense of the dorsal edge. At the lower part 

 is found the articulation for the quadrate. 



The outer face is rounded. The greatest width of the ramus 

 is at about the middle of the bone. At the dorsal edge there 

 is a depression ventral to the teeth. 



The inner face of the mandible is made up of the inner 

 faces of dentary and articulare. There is a large cavity pos- 

 terior to the teeth, extending anteriorly. At about the mid- 

 dle the upper part of the face is cut off, and ventrally a long 

 ramus extends posteriorly along the ventral edge of the articu- 

 lare. 



There are three bones in the mandible to be described. 

 The splenial is reduced and is seen merely as a splint, and can- 

 not be described separately. The other three bones are the den- 

 tary, articulare and angulare. 



Dentary. (Plate XXV, Den.; plate XXXVI, figs. 61, 62, 63.) 



The dentary is the largest bone in the mandible, and in de- 

 scribing it one almost defines the whole mandible. The anterior 



a-Univ. Sci. Bull.. Vol. IV. No. 16. 



