ADAMS: SKULL OF THE WOLF-EEL. 343 



the face, and between this ridge and the edge the face is de- 

 pressed. Starting at the anterior edge of the face are two 

 large cavities which extend posteriorly. The whole face is 

 honeycombed, the pits extending in regular lines. The anterior 

 end of the bone is forficate, and the articulation with the eth- 

 moid is formed in this way, the posterior part of the ethmoid 

 being wedge-shaped and fitting into this cavity. 



Lateral Face (anterior). (Plate XXXI, fig. 35.) 



The anterior lateral face is formed by the anterior end be- 

 ing beveled toward the ventral edge. This face is concave both 

 ways and at the posterior end turns out laterally. There are 

 two cavities at the postero-ventral part of each face, extending 

 posteriorly into the bone. Just posterior to this face there is 

 a depression for the articulation of the suborbital ring; at the 

 center of this depression there is a foramen, extending pos- 

 teriorly also. The ventral end of the frontal is hollow and 

 sheaths the ethmoid in this cavity. 



Articulations. 



The frontal has eight articulations : Posteriorly with the 

 parietal, by overlapping it ; with the supraoccipital by a sharp 

 groove in the posterior end ; with the sphenotic by this bone 

 overlapping the frontal ; ventrally with the alisphenoid, which 

 lies against the ventral wing on the inside; with the para- 

 sphenoid by the drawn-out ventral edge; with the suborbitals 

 at the posterior part of the enlarged anterior end of the 

 frontal ; with the ethmoid anteriorly, and with the prefrontals 

 at the anterior end of the lateral faces. ^ 



Prefrontal. (Plates XXV, XXVI, XXVII; plate XXXII, figs. 37, 38, 39.) 



The prefrontals are irregular bones lying on each side of 

 the ethmoid. The posterior face is concave and points poste- 

 riorly and dorsally. This face is smooth and has a large proc- 

 ess, springing from the ventral inner portion, which articu- 

 lates with the ethmoid, parasphenoid and the other prefrontal. 

 There are two depressions in the outer edge, immediately ven- 

 tral to the smooth dorsal face, which articulates with the sub- 

 orbital ring; one depression or notch is cut out at the expense 

 of the upper edge, and the posterior notch at the expense of the 

 lower. 



The inner ventral edge drops ventrally and forms a large 

 process for articulation on the ventral and inner face. This 

 process is very irregular. At the anterior part there is a 



