— 117 — 



represented in that part of that surface that lies between thc tvvo diverging, posterior portions of tlic 

 articular ridge near its lateral edge. The ventro-lateral corner of the wing of the bone of Trigla, which 

 forms a sharp spine-like corner, is certainly the homologue of the rounded angle in the lateral edge of 

 the wing of Scorpaena, and the anterior end of the anterior, single portion of the articular ridge of 

 Trigla must be the homologue of that process-like portion of the bone of Scorpaena that gives artic- 

 ulation to the palatine. The lachrymal articular process of the bone of Scorpaena must then be 

 represented in some part of the articular ridge of Trigla that lies between its anterior and posterior cnds. 



The small orbital surface of the ectethmoid of Trigla is strongly concave, converging forward 

 and inward to a large opening which leads into the hind end of a large median chamber in the ant- 

 orbital cartilage, the chamber perforating the extreme ventro-anterior portion of the interorbital 

 septum. This chamber is bounded laterally, on either side, by the primary portion of the corre- 

 sponding ectethmoid, and its floor is perforated by a circular opening which is closed ventrally by 

 the underlying jjarasphenoid. From the chamber, on either side, a canal leads forward into the 

 nasal pit and transmits the olfactory nerve of its side, this canal lying between the mesethmoid and 

 ectethmoid bones and becoming, in my large specimens, a large vacuity in those two bones, filled 

 with loose fatty tissue. Anterior to this vacuity, there was, in the mesethmoid bone alone of the 

 three specimens examined in this connection, a separate median vacuity, already referred to, which 

 opened ou the ventral surface of the bone. The oblique muscles of the eye extend into the median 

 Chamber and have their origins there, the chamber thus being an anterior eye-muscle canal. Imme- 

 diately lateral to the opening that leads from the orbit into the anterior eye-muscle canal, there is, 

 in the ectethmoid, a small canal which transmits an artery coming from the orbit. Considerably 

 lateral to this canal there is another smaller canal, also in the ectethmoid, but no structure, either 

 nervous, arterial or venous could be found traversing it. 



The XASAL is a somewhat quadrilateral bone that forms the antero-lateral corner of the 

 casque-hke dorsal surface of the skull. The lateral portion of its hind end rests upon the dorsal 

 surface of the ectethmoid. Its mesial half overlaps externally and is quite firmly bound to the lateral 

 portion of the dorsal surface of the mesethmoid. Its anterior edge forms the lateral portion of the 

 concave anterior edge of the casque of the skull. Its antero-lateral corner projects beyond the under- 

 lying corner of the mesethmoid and also beyond the anterior palatine articular eminence of the ethmoid 

 cartilage, and is thickened by accretions to its ventral surface. This thickened portion rests partly 

 upon the dorso-lateral surface of the base of the maxillary process of the palatine, and partly upon 

 the external surface of a small flat process on the dorsal edge of the lachrymal. The lachrymal and 

 palatine are here immoveably bound together, and the extent of the contact of one or the other with 

 the nasal varies in different specimens. The nasal is strongly but somewhat loosely bound by dermal 

 or fibrous tissues to both the palatine and lachrymal, and gives sliding articulation to them when 

 the palato-quadrate and cheek-plate swing inward and outward; the sliding contact being mainly 

 with the lachrymal. The ventral surface of this corner of the nasal closely approaches, and, as already 

 stated, may even rest upon the summit of the anterior palatine process of the ethmoid cartilage, 

 the palatine articulating with the latter process by an articular surface at the base of its maxillary 

 process. 



Between the summit of the anterior palatine process of the ethmoid cartilage and the projecting 

 antero-lateral corner of the mesethmoid, the nasal roofs a large passage which leads from the rostral 

 ■depression into the anterior end of the nasal pit. The nasal pit is a deep low fossa in the lateral edge 



