254 Dl{. W. O. KIDEWOOD ON THE 



relatively short ; they do not extend over the ethmoid region^ 

 tlie enlarged nasals constituting the roofing-bones of this part of 

 the cranium. Tiie nasals are important bones, suturally united 

 with the frontals, with the mesethmoid, and with one another, 

 and also united by their edges with the preorbitals and pre- 

 niaxillie. They cover the prefrontals completely. 



The mesethmoid is a small rhombic bone of ectosteal origin. 

 The nasal, frontal, and mesethmoid bones, and the upper portion 

 of the squamosal are sculptured. The opisthotic is comparatively 

 large ; its ventro-lateral angle is united with a backwardly 

 directed process of the pro-otic. The postfrontal does not 

 present itself in a dorsal view of the skull, but is covered by 

 the frontal, squamosal, and postorbital bones. Neither orbito- 

 spheuoid nor basisphenoid bone is present. 



The lateral temporal groove is partially roofed over by a 

 lateral growth of the squamosal. The margin of the posterior 

 temporal fossa is bounded by the epiotic and squamosal, these 

 bones uniting both above and below it. The vacuity passes 

 forwards and slightly inwards, but does not end blindly in front; 

 it curves outwards and opens laterally into the lateral temjioral 

 groove between the postfrontal and squamosal. This aperture 

 appears at first glance to correspond with the " temporal foramen " 

 of the Clupeoids ; but it must be remembered that the latter 

 foramen leads directly into the cranial cavity, and is bounded by 

 the parietal and frontal bones. The subtemporal fossa, lying 

 immediately below the squamosal portion of the articular facet 

 for the head of the hyomandibuhir, is a fairly large pit, bounded 

 by the pro-otic, exoccipital, opisthotic, and squamosal. 



A rod-like process of the parasphenoid rises on each side to 

 meet the aliisphenoid, but it does not reach the postfrontal, as 

 it does in Osteoglossum formomm (Bridge, 7. c. p. 302 and pi. 22. 

 fig. 1). From the lower part of this process of the parasphenoid 

 there projects a lateral peg-like outgrowth which articulates with 

 the entopterygoid and hyomandibular. A small clump of sti'ong 

 teeth is situated on the ventral side of the parasphenoid just 

 behind the articulation, and these teeth, together with those of 

 the two entopterygoids, engage with tlie lingual teeth borne by 

 tbe median constituents of the hyobranchial skeleton. The 

 parasphenoid extends a little more posteriorly than the basi- 

 occipital. The eye-muscle canal does not open postei'iorly ; 

 there is a distinct hole behind the parasphenoidal teeth, but this 



