THE MOEMTETDJE, KOTOPTEllIDjE, AND HTODONTID^. 205 



articulates with the side of the vomer. There is no sur- 

 masilla. 



Mandibular Series (figs. 12 and 16). — The angular is distinct, 

 and of large size. The dentary bears a row of pointed teeth on 

 its outer edge, and crowded small teeth on its supero-internal 

 surface. There are two lines of serrations in each ramus of the 

 mandible, one along the ventral edge of the dentary and angular, 

 and another on the outer face of the dentary. A sesamoid 

 articular of moderate size is present ; the endosteal articular is 

 not distinct from the ectosteal articular. 



Syopalatine Series (fig. 16). — The hyomandibular articulates 

 with the cranium by a single broad head. The symplectic is 

 much expanded, and unites suturally with the lingual faces of 

 the preopercular, the metapterygoid, and the quadrate. Teeth 

 are borne by the palatine, ectopterygoid, and entopteiygoid. 

 The palatine articulates with the ethmoid region by a single 

 head. The ectopterygoid is fused with the palatine, and its 

 lower edge is nearly straight, and has no angulation in the 

 middle of its length. 



Opercular Seines (fig. 12). — The opercular bone is compara- 

 tively small in size, and is marked by shallow radiating ridges. 

 The size of the gill-cover is considerably larger than that of 

 the opercular bone would lead one to suppose ; there is a broad 

 posterior margin not supported by bone. There is no sub- 

 opercular bone. 



The branchiostegal I'ays are eight in number ; they are all 

 curved rods, and the posterior ones show very little tendency 

 towards flattening. The first two lie free in the branchiostegal 

 membrane, the third is attached to the edge of the ceratohyal, 

 and the remaining five to the outer face of this bone, the last, 

 which is the largest, overlapping much more of the bone than 

 the others. None are attached to the epihyal. 



EyolrancMal Series (fig. 17). — There are twelve long and 

 rather stout gill-rakers on the first branchial arch, but those on 

 the other branchial arches are short and blunt. They are all 

 readily removable from the underlying bone. The interhyal is 

 cartilaginous, or is very slightly ossified. 



The epihyal is small as compared with the ceratohyal, and the 

 hypohyal is small, and single on each side. It is probably 

 the lower of the two hypohyals which is wanting, or unossified, 

 since the anterior ligaments of the urohyal, usually connected 



