11 277 



has its somewhat thickened upper margin firmly fastened below the edge of 

 the broadest proximal part of the mesethmoid, reaching with a slender splint to the 

 preorbital. 



On the inner face of tlie suspensory apparatus two oblique ovoid patches of 

 teeth are present, the anterior one on the entopterygoid *, the posterior on the 

 metapterygoid. 



The short ascending part of the preoperculum covers not only most of the 

 lateral face of the hyoniandibular, but also the front face below the hyomandibular 

 foramen; the long horizontal part is on the outer face ornamented with fine striæ 

 and reaches almost to the articular head of the quadrate. 



The premaxilla (PI. I, fig. 4 i), which bounds the mouth slit, is slender and 

 edentulous, provided with the typical processes, as also is the case with the rela- 

 tively large, posteriorly broadening maxilla (mx). 



The articulation for the lower jaw is situated at a distance rather far behind 

 the end of the snout; the mandible therefore is fairly long, and the mouth 

 opening is extensible to a considerable degree. The mandible is high and laterally 

 compressed, composed of the typical three parts; the angular (an) is very small and 

 therefore easily overlooked. Two patches of teeth are found on the dental, an ante- 

 rior small one on the upper edge close to the symphysis, and a large posterior 

 one covering the upper part of the inner face. 



Branchial apparatus. The whole gill-bearing part lies behind the articu- 

 lation of tlie hyoid to the skull. The hyoid (PI. II, fig. 7, 8) is composed of the typi- 

 cal elements, but the epihyal (eh) and the lower hypohyal (hy') are unusually 

 large in proportion to the other constituents. The stylohyal (st) is laterally 

 compressed and broadens towards the upper end, the inner face of which plays 

 against the thin cartilage interposed between the hyomandibular and the sym- 

 plectic. 



The branchiostegals are four in number, belonging to the outer face of the 

 epihyal, the uppermost is the stoutest and longest, at its end divided into filaments. 

 The glossohyal is long and slender, surpassing in length the hyoid and the uro- 

 hyal, which is laterally compressed and higher behind, where it is broken up into 

 filaments. The first copula (PI. II, fig. 3 co ') or basibranchial is represented by a 

 short cartilage, the second (co'^) is slender, styliform and osssified; no further co- 

 pulæ are developed. 



The gill-arches (PI. II, fig. 3, 4) are provided with rows of thin bony plates, 

 densely beset with teeth, in the place of gill-rakers. Along the whole anterior bor- 

 der of the first arch plates of this kind are found, from the upper to the lower 

 end, the first gill-slit being very wide; otherwise the plates are mostly confined to 

 the margins of the ceratobranchials only, those on the anterior border always 

 being somewhat larger. The first arch consists of three parts, having no pharyngo- 



* The anterior patch of teeth has been seen by Günther (16 a p. 536), but he ascribes it to tlie 

 "palatine bones". 



36* 



