182 PROF. W. K. PARKER ON THE MORPHOLOGY 



in the two vomers. The premaxillary (px) yields a very large transversely oblong 

 plate to the palate in front ; the dentary margin is only gently arcuate, and the 

 ascending nasal process (figs. 5, 7) is a smallish wedge. The maxillary (mx) gives off 

 a considerable palatine plate, and is of great height in the cheek (fig. 7) ; its long jugal 

 process is arched downwards, and only reaches two thirds of the distance from the high 

 part of the bone to the quadrate (q). These bones, as also all the subcutaneous scutes for 

 this strong skull, arc rough on their outer surface. 



The nasals (n) are large, thick, scabrous, multilobate plates ; their strong median 

 suture is notched before and behind, — before to receive the apex of the nasal process 

 of the premaxillary, and behind to form, with the frontals (f), a small fontanelle. 

 This space communicates with the more regular opening between the vomers below; 

 and this merely functionless cavity is the adult remnant of the "middle nasal passage" 

 seen in the larva (figs. 1, 2). 



The frontals (/) are bevelled at their antero-external angle, to receive the outer nasal 

 roof-bone, or external ethmoid (e.eth). This is a roughly pentagonal plate; it cor- 

 responds with the bone which ossifies the prefrontal of an Osseous Eish, but is parosteal 

 in these types. 



The orbito-nasal nerve runs in between this bone and the maxillary in the lacrymal 

 region (fig. 7). The frontals are imbricated on the parietals (p,f) ; they scarcely exceed 

 them in length, but are broader. This breadth is gained by the development of a much 

 better orbital rim than is seen in Salamcmdra (PI. XVI.). 



The free outcurved part of the rim reaches to the squamosal ; in front, it is 

 finished by the ectethmoid ; and below, the jugal process of the maxillary almost com- 

 pletes the bony circle of the eye. The ruga3 and their interspaces, especially between 

 the inner and outer part of the frontals, very much resemble what is found in so many 

 Teleostean Fishes. The parietals (p) really form a wall in this species as well as a roof; and 

 a strong ridge, which converges in a subarcuate manner towards its fellow behind, makes 

 a very definite upper boundary to the temporal fossa. The size of the muscles causes the 

 skull to have a waist at that part ; and the fossa itself is completely surrounded by bone. 



The parietals end behind abruptly, the temporal ridges in each angle projecting some- 

 what ; but each bone is lifted and bevelled a little over the junction of the anterior and 

 posterior canals (a.sc, p.sc). 



The frontal and sagittal sutures run on to the end, and in front is the nasal suture, 

 over the snout ; these are roughly denticulate. 



The side view (fig. 7) shows how well made are the orbital plates of the frontals and 

 the temporal plates of the parietals. 



The hammer-shaped squamosals (sq) have their supratemporal equal to their preoper- 

 cular region ; the former is roughly ribbed along its outer edge above, and the latter is 

 carinate, the keel running down into the pointed lower end, and binding on the quadrate (q). 



The fiat top of the squamosal (fig. 5) is scabrous ; its supratemporal part is twice as 

 large as its postfrontal projection. A notch behind, under the teginen, exposes the 

 otic process. 



