— 142 — 



the anterior end of the maxillary process of the palatine. This process of tlie palatine is, as in Trigla, 

 closely bound to the dorso-mesial edge of the lachrymal, and from the adjoining edges of these two 

 bones a strong ligament arises and has its attachment on the dorsal surface of the maxillary. This 

 ligament, as already stated, apparently represents the distal half of the rostro-palatine ligament 

 of Scorpaena. The ethmo-maxillary ligament is represented by a short ligament that extends from 

 the ascending process of the maxillary to the ventral surface of the nasal, at the.base of its process- 

 like antero-lateral corner. There is no ligamentary process either on the external or internal surface 

 of the bone, this doubtless being in causal relation to the slightly developed condition of the maxillo- 

 mandibular ligament and of that tendon of the adductor mandibulae that has its Insertion on the 

 maxillary. 



The NASAL is a flat quadrilateral bone, which rests, in large part, directly upon the dorsal 

 surface of the thin flat anterior portion of the antorbital cartilage. In the anterior two-thirds of its 

 length it suturates, in the middle line, with its fellow of the opposite side. Posteriorly it diverges 

 slightly from the middle line, leaving a V-shaped space between itself and its fellow of the opposite 

 side, this space receiving the pointed anterior end of the mesethmoid. The narrow bind end of the bone 

 suturates with the mesethmoid, slightly overlapping that bone externally. Laterally, the posterior 

 half of the bone suturates with the long anterior end of the ectethmoid, in the manner already des- 

 cribed. The dorsal surface of this part of the bone is deeply grooved, near and parallel to its lateral 

 edge, for the second primary tube of the supraorbital lateral canal, as also already described. A narrow 

 wall of bone alone separates the extreme anterior end of this groove from the hind end of the nasal 

 incisure. The antero-lateral corner of the bone is prolonged into a short stout horn-like process which 

 rests upon the sumniit of the anterior palatine process of the ethmoid cartilage. On the lateral sur- 

 face of the anterior end of this process there is the large opening of the anterior primary tube of the 

 supraorbital latero-sensory canal, this tube opening on the outer surface by a single large pore. 

 The bone is traversed by the supra orbital latero-sensory canal, and lodges one organ of the line. 



The lateral half of the nasal is thickened, its füll length, and this thickening would seem to be 

 due to the fusion, with the usual dermal component of the bone, of a thin underlying plate of bone. 

 This underlying plate lies directly upon the cartilage of the snout, and projects slightly beyond the 

 overlying portion of the nasal, both anteriorly and laterally. The laterally projecting portion of the 

 plate forms the floor of the nasal pit, while the anteriorly projecting portion overlaps externally the 

 hind edge of the ascending process of the vomer. The antero-lateral corner of the plate lies directly 

 beneath but is separated by a very narrow slit from the process-like antero-lateral corner of the 

 dorsal, dermal portion of the bone, and here approaches and gives support to the base of the but 

 slightly developed anterior palatine process of the ethmoid cartilage. This latter process forms, as 

 in Trigla, the antero-lateral corner of the thin flat cartilage of the snout. 



The ventral plate of the nasal of Peristedion thus occupies somewhat the position of the cor- 

 responding half of what I have described, in Trigla, as the perichondrial portion of the mesethmoid 

 of that fish. It also occupies much the position of the plate that I have described, in Belone, as under- 

 lying the dermal component of the nasal of that fish. In Peristedion, as in Belone, it separates from 

 the underlying cartilage, in slightly boiled specimens, without breakage of the cartilage, and hence 

 would seem to be of menibranous origin, but this was not carefully investigated. Two suppositions 

 suggest themselves regarding it. The one, that there is a predisposition in the tissues of this region 

 to the development of this plate, and that the plate attaches itself to the mesethmoid or nasal. 



