i04 RECORDS OF THE AUSTRALIAN MUSEUJL 



olfactory region as two rounded prominences (a.p.e.). Situated 

 under the projecting dorsolateral ridge is a small aperture, 

 probably for the passage of the cerebral-carotid artery. The 

 ventral border projects posteriorly into the floor of the orbito- 

 sphenoidal region, thus differing from Ghaperina, in which the 

 postero- ventral edge is broadly emarginate 



The palato-quadrate " bow " is very strong, and is stronger than 

 in Chaperina fusca. This applies more to the pterygoid and 

 suspensorial segments of the arch, the palatine element being of 

 much the same development. 



The palatine bone (pal.) is nearly straight and sub-cylindrical ; 

 it is stouter and slightly arched towards the outer third of its 

 length. Mesially it broadens out into a large flat plate (PL ix., 

 fig. 2, p. pi.) which forms a suture in the mid-line with its fellow, 

 and posteriorly with the parasphenoid. This last character, the 

 palatine plate is characteristic, and is not present in Chaperina 

 fusca. In that genus the palatine is not cylindrical but flattened, 

 and produced anteriorly into a process underlying the vomer, 

 which however could not be considered homologous with the 

 palatine plate. The ethmoidal segment or anterior third of the 

 palatine, is raised into a distinct keel, which does not continue to 

 the median suture of the plates. By the possession of this keel 

 it also differs from Chaperina fusca. The post-palatine segment 

 forms a suture with the pterygoid, and is supported by the 

 palatine lamina of the maxilla. 



The pterygoid (pt.) is a large sigmoid bone, which attains a 

 greater development than in Chaperina fusca. Its anterior end 

 forms a suture with and lies over the palatine, while the rest of 

 the anterior third forms a long sinuate suture with the maxilla, 

 and is supported by the palatine lamina of that bone. The pedicle 

 branch is short and twisted. The posterior segment runs along 

 the inner and posterior side of the suspensorium. This bone is 

 compressed, and bears a dorsal and ventral ridge, giving it the 

 characteristic twisted appearance. 



The paraquadrate, tympanic or squamosal (pqu.), is moderately 

 developed and well ossified. The main shaft is spatulate and 

 welded on to the suspensorium anteriorly. The otic process is 

 thin and curved with an angular posterior edge. The zygomatic 

 process (z. pr.) is somewhat irregular and slightly curved, being 

 directed forwards and inwards. 



The quadrate (qu.) is stout, bears a rather small condyle, and 

 forms the core of the suspensorium. Seen from above it appears 

 wedged in between the distal half of the paraquadrate and the 



