SGi Dr. W. G. Ridewood on the 



from tli(^ prefrontals by a considerable tract of ethmoid 

 cartikigo. 



The post-temporal consists almost entirely of its epiotic 

 limb^ tlic only other part being a delicate sensory-canal scale 

 oE tuhular shape and horiztnital disposition. The anterior 

 end of this tube is in contact with another tubular scale, 

 which represents the supratemporal, but has not the tri- 

 radiate form characteristic of the supratemporal bone in 

 Malacopterygian fishes generally, since tlic forking of the 

 horizontal sensory canal into the supraparietal commissure 

 and the squamosal branch occurs just in front of it, and not 

 within it. 



From the opisthotic there extends a rod of bone, a kind of 

 intermuscular bone, in the direction of the post-temporal, 

 whicli, however, it fails to reach. Fibrous tissue intervenes 

 between its jaosterior extremity and the post-temporal, and 

 the relations between the intermuscular bone and the post- 

 temporal are such as to open up an interesting question 

 whether the opisthotic limb of the post-temporal has not in 

 Teleostean fishes generally the morphological value of an 

 ossified ligament or intermuscular bone. In view of the 

 dermal origin of the post-temporal and the depth below the 

 surface at which its opisthotic limb occurs it is highly 

 probable that such is the case. In Gonorlnjnchus a second 

 and similar intermuscular bone runs from the back of the 

 exoccipital parallel with the above, but situated nearer to the 

 median plane and having no connexion with the post- 

 temporal bone. Such intermuscular bones are not uncommon 

 in Teleostean fishes, and a comparative account of them is 

 given in the ' Proceedings of the Zoological Society/ 1901, 

 ii. pp. 59, 65, 66. 



The nasal is a long slender bone of tubular shajie, and the 

 preorbital (fig. 5, jjor) is large and has a conspicuous keel 

 near its lower edge, as ali'cady shown by Smith Woodward 

 (Proc. Zool. Soc. 1896, p. 503, and fig. 5, x). There are no 

 suborbital or postorbital bones. 



The gape is bounded above by the ])remaxilla3 alone, 

 although the maxilla is about twice as long as the premaxilla, 

 and extends more anteriorly than that bone, as well as more 

 posteriorly. The premaxilla articulates M'ith the ventro- 

 external surface of the maxilla at about one third of the 

 length of the latter from its anterior end ; a short proL-ess of 

 the premaxilla extends in front of this articulation, but the 

 main part projects backward and downward. The extreme 

 anterior end of the maxilla articulates with the cartilaginous 

 anterior termination of the palatine. There is no articulation 



