— 118 — 



of tliis part of the skull, lying between the nasal above, the mesethmoid and the cartilage of the 

 snout mesially and below, tbe ectethmoid posteriorly and below, and the anterior palatine process 

 of the ethmoid cartilage anteriorly. The pit is not large enough to lodge the entire nasal sac, a part 

 of the sensory portion of the sac extending laterally, beyond the lateral edge of the skull, onto the 

 dorsal surface of the palatine, and there lying between the palatine and lachrymal bones. A mesial 

 diverticulum of the sac, corresponding to that in Scorpaena but somewhat differently disposed, runs 

 forward and mesially through the passage that leads from the nasal pit into the rostral depression, 

 and then turns mesially behind the rostral, between it and the anterior end of the mesethmoid, and 

 abuts against but is apparently not continuous with its fellow of the opposite side. 



The nasal bone is traversed by the supraorbital latero-sensory canal, and lodges one organ 

 of that line, the anterior opening of the canal lying at the extreme antero-lateral corner of the bone. 

 De Sede de Lieoux ('84, p. 111) says that the cephalic portion of the latero-sensory canals is absent 

 ,,chez les Trigles", Trigla hirundo being the species particularly examined. This is far from being 

 true, as will appear in the course of my descriptions. 



The VOMER has ascending processes which are in contact, posteriorly, with the anterior end 

 of the thin perichondrial layer of the mesethmoid. The ascending processes of opposite sides enclose 

 between them, as in Scorpaena, the anterior portion of an internasal ridge of cartilage, the bone and 

 cartilage here being, in medium-sized specimens, raised into a slight ridge, while in large specimens 

 they become a prominent knob with a flat summit. The cartilaginous rostral slides backward and 

 forward on this ridge or knob. The lateral corner of the ascending process of the vomer is slightly 

 raised and embraces the anterior edge of the base of the anterior palatine process of the ethmoid 

 cartilage; this raised or process-like portion of the vomer of Trigla corresponding strikingly, in position, 

 to the septomaxillaries of Sagemehl's figures of the Cyprinidae. Antero-mesial to this little process 

 there is a rounded eminence, prominent in large specimens, near the anterior edge of the dorsal surface 

 of the bone. The lateral surface of this eminence, and the slight hollow between it and the palatine 

 process, give articulation to the ventral edge of the ascending process of the maxillary, a päd of tough 

 fibrous or semi-cartilaginous tissue lying between the two surfaces. 



The ventral surface of the convex anterior edge of the vomer is slightly raised, and is furnished 

 with an uninterrupted band of small villiform teeth. Immediately posterior to the lateral end of this 

 band of teeth, there is a large depression which gives Insertion to the very slightly developed vomero- 

 palatine ligament. A slightly developed lateral process projects postero-laterally, extending beyond 

 the anterior edge of the ventral plate of the ectethmoid and there lying upon the ventral surface of 

 that plate. 



In Trigla lineata the anterior end of the vomer is bent abruptly , though but slightly, downward ; 

 and although this is a natural formation, it has decidedly the appearance of having been produced by 

 a blow on the end of the snout of the fish. 



The PREMAXILLARY has a broad oral surface, covered its füll length with small villiform 

 teeth. At about the middle of the length of the bone, there is a thin flat postmaxillary process directed 

 backward and slightly upward. This process forms the hind end of a pronounced longitudinal ridge 

 on the internal surface of the bone, this ridge representing a thickened part of the bone, of membrane 

 origin, which lies slightly dorsal to its tooth-bearing portion. This membrane component of the bone 

 has a thin, flat and rounded hind (distal) end, which forms the postmaxillary process of the bone, and 



