LBPIDOTLTS. 31 



spaced series of six or seven styliform teeth. Its hinder half tapers baci< wards to 

 a bhmt point, which meets the maxilla ; its anterior half is continned upwards in 

 a narrow laminar process, which is so long that (as in Amia) it passes beneath the 

 nasal bone to articulate in a squamous suture with the inner face of the frontal 

 (PL V, fig. 6, pm,r.). This process, also as in Amia, is hollowed on its superior 

 face and pierced by a large oval vacuity. The mandible is short and much 

 deepened in the coronoid region. As seen from the outer face (PI. VI, dkJ.) the 

 angular l)one is comparatively short and deep, and marked near its lower margin 

 by a row of large pits and rugosities for the slime-canal. The dentary bone 

 (PI. VII, fig. 2) is still deeper in the coronoid region just in front of the angular, 

 but rapidly contracts to the tooth-bearing portion, which forms a narrow bar 

 curving inwards and slightly deepening at the symphysis. This portion bears a 

 regular spaced series of nine or ten styliform teeth somewhat larger than those of 

 the upper jaw ; while its outer face is a little rugose and bears a row of large pits 

 for the course of the slime-canal The summit of the coronoid region is formed 

 by a long and narrow coronoid bone, exactly as in Amia (seen in PI. VI). The 

 articular end of themeckelian cartilage is slightly ossified (seen in B. M. no. 41157), 

 and on the inner face of the mandible onh^ one splenial element has been observed. 

 This is comparatively stout, enters the mandibular symphysis, and bears a cluster 

 of about three rows of teeth which are stouter than those of the dentary and 

 diminish to comparatively small teeth behind (PI. V, fig. 0, vkL). All the teeth are 

 hollow and fused with the supporting bone, not in sockets. When unworn the 

 smooth and rounded enamelled crown rises to a sharp median apex, while the com- 

 paratively long pedicle is slightly SAVollen just below the crown and a little 

 expanded at its base, which sometimes exhibits short vertical grooves. Successional 

 teeth have been observed as in other species of Lepidotus. 



In the hyoid arch the ceratohyal is relatively large, laterally conjpressed, 

 constricted in the middle, and deepest behind (PI. V, fig. 8, eh.). It does not 

 appear to bear any branchiostegal rays. 



The preoperculum, best seen in PI. V, fig. 8, pop., but also shown in PI. V, 

 fig. (3, and PI. VI, is narrow and gently curved at the angle. The ascending 

 limb is slightly constricted in its lower half, but expands upwards where its outer 

 face is smooth and its truncated end is in contact with the scjuamosal bone. Its 

 curved lower limb is more expanded and traversed by the usual longitudinal ridge, 

 behind and below which the large openings of the slime-canal are conspicuous. 

 The anterior border exhibits a smooth overlapped surface for the cheek-plates as 

 far as this ridge ; while the expansion behind, when unabraded, is marked by a 

 few radiating crimpings, and the posterior edge usually bears a spaced row of 

 large tubercles of ganoine. The operculum, also best seen in PI. V, fig. 8, op., 

 where the postero-superior angle alone is incomplete, is somewhat wider below 

 than above, and its maximum width measures about three-fifths of its depth. Its 



