— 141 — 



There is a broad rounded incisure between the two ascending processes, tlie incisure embracing the 

 anterior end of a small median interspace of cartilage whicli lies between this incisure and a median 

 incisure between the adjoining anterior edges of the ventral plates of the nasals. Directly anterior 

 to the incisure in the vomer, there is a very small median eminence on the anterior edge of the bone, 

 and midway between this eminence and the lateral edge of the bone there is a larger eminence, also 

 on the anterior edge of the bone. Running dorso-laterally from this latter eminence there is a slight 

 ridge which terminates in an eminence on the dorsal surface of the ascending process of the bone. 

 Lateral to this ridge and eminence there is a broad and shallow groove which gives articulation, through 

 the intermediation of a päd of tough fibrous tissue, to the postero-mesial surface of the ascending 

 process of the maxillary. Lateral to this articular groove, the ascending process of the vomer bounds 

 and Supports the anterior palatine process of the ethmoid cartilage. 



The ROSTRAL is pyramidal in shape, as in Trigla, and gives support, on its anterior surface, 

 to the ascending processes of the premaxillaries. Its internal surface rests upon the little median 

 interspace of cartilage on the dorsal surface of the snout, and also on the adjoining portions of the 

 ascending processes of the vomer. This interspace of cartilage lies considerably anterior to the nasal 

 pits, as it does in Trigla, instead of being internasal in position, as it is in Scorpaena. 



Whether there is in Peristedion, as in Trigla, a diverticulum of the nasal sac of either side 

 that extends into the rostral depression, was not investigated ; but it would seem not, the space 

 beneath the anterior end of the nasal seeming too small to permit it. 



The PREMAXILLARY is a slender untoothed bone, with a large flat and thin postmaxil- 

 lary process, and small ascending and articular processes. The proximal end of the shank of the 

 bone is bent so as to project postero-ventrally and slightly mesially, and from the base of this beut 

 portion the short ascending process arises; this process and the proximal end of the bone together 

 forming a straight edge, and together looking like the flattened and broadened proximal end of the 

 bone. This straight edge of the bone lies close to its fellow of the opposite side, the ascending process 

 being directed dorso-anteriorly instead of dorso-posteriorly. From the dorso-anterior end of the 

 process, or from the rostral immediately posterior to it, a ligament arises, and running ventro-postero- 

 laterally is inserted on the maxillary at the base of the ascending process of that bone. This ligament 

 is apparently the homologue of one half of the rostro-palatine ligament of Scorpaena and Trigla, 

 the other half of the ligament arising on the maxillary, close to the point of Insertion of this one, 

 and extending from that bone to the palatine. The articular process of the premaxillary is small, 

 is directed dorso-posteriorly, and articulates with a large but low articular eminence on the anterior 

 surface of the proximal end of the maxillary. 



The MAXILLARY has a slender shank, with its distal end abruptly expanded. On the anterior 

 surface of the proximal end of the bone there is a large oval eminence which gives articulation to 

 the premaxillary, the long axis of the eminence being directed dorso-distally across the anterior 

 surface of the bone. From the dorsal edge of the bone, in the line of the axis of the articular eminence, 

 the ascending process of the bone arises, the process lying transverse to the shank of the bone and 

 being directed dorso-postero-laterally. The postero-ventral edge of the process is thickened, and 

 has a sliding articulation with the dorsal surface of the ascending process of the vomer, in the groove 

 already described, the articulating surfaces being separated by a päd of tough fibrous tissue. In the 

 angle between the distal surface of the process and the shank of the bone, is the articular surface for 



