CBAKIAl/ OSTEOLOOr OF THE 0STE0GL03SID^. 255 



ends blindly in front. The front of the vomer boards two large 

 teeth and a few smaller ones. 



Temporal and Preopercular Series'^' (PI. 30. figs. 4 and 5). — The 

 body of the post-temporal is small and horizontally disposed, and 

 its sensory canal is continued forwards into the supratemporal. 

 It has two limbs, nearly equal in length — a superficial one to the 

 top of the epiotic, and a deep, more rod-like one to the back of 

 the opisthotic. The supi-atemporal is a curved tubular bone, 

 lying close behind the transverse crest of the squamosal and 

 parietal, with, which bones it is in close fibrous union. 



The preopercular is sculptured in its lower part, but not in its 

 upper part, which is overlapped by the postorbital plates. The 

 lower limb of the preopercular is not quite half as long as the 

 upright limb, and makes with it an angle of rather less than a 

 right angle. The interopercular lies on the inner surface of the 

 preopercular and is not sculptured. 



Oircumorbital Series (fig. 4). — In addition to the nasal bone, 

 which has already been considered in dealing with the cranium, 

 there are six bones of the circumorbital series. They are all 

 sculptured. The t\\ o postorbitals are very large, and the pre- 

 orbital and suborbital are closely bound by fibrous tissue to the 

 upper edge of the maxilla. 



Maxillary Series (fig. 4). — The premaxillae are small in size : 

 they are not freely movable, but are closely connected by their 

 posterior edges with the front of the mesethmoid and nasal 

 bones. They carry four or five teeth each. The mazillje are 

 long bones extending nearly as far back as the mandibular arti- 

 culation. Each bears a single row of 35 to 40 sharply conical 

 teeth, which diminish in size from before backwards. Both 

 premaxilla and maxilla are sculptured. There is no surmaxilla. 



Mandibular Series (figs. 4 and 5). — The dentary is long, with 

 a single row of about 35 teeth, diminishing in size from before 

 backwards. The angular is distinct from the articular, and a 

 sesamoid articular is present. The exposed parts of the deutarv 

 and articular are sculptured. The articular facet for the head of 

 the quadrate is formed by the articular alone. 



* The reasons for including the preopercular and interopercular bones in 

 this series, and for excluding them from the opercular and branchiostegal 

 series, are given in a former paper (Proc. Zool. Soc. 1904, ii. pp. 68 & 75;. 

 For reasons given in the same paper it is considered expedient to regard tJia 

 Dost-temporal as a coDStituent of the skull. 



