618 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxvii. 



single concave occipital condyle, as described elsewhere. The audi- 

 torj'' bulla is rather prominent and there is a very large area of carti- 

 lage between the exoccipitals, parasphenoid, basioccipital, and prootic. 

 The myodome is moderate in size and is not continued back in a tube. 

 The supraoccipital slightly separates the posterior ends of the f ront- 

 als. Its crest is developed posteriorly, scarcely extending above the 

 rest of the cranium. The epiotic is somewhat covered b}- the parietal. 

 The surface that receives the posttemporal ; lopes steeply downward. 

 The opisthotic bends up at a right angle around the posterior surface 

 of the exoccipitals and pterotic. The f rontals are wide and truncate 

 anteriorl}^; they do not extend forward of the ethmoid. The para- 

 sphenoid sends up the usual basitemporal wing, but without an open- 

 ing behind it into the mj^odome. It ends in a sharp point on the 

 basioccipital some distance from the occipital condyle. The basi- 

 sphenoid sends down a slender process, which just reaches to the 

 parasphenoid. The alisphenoids do not meet at the median line, 

 leaving a wide opening between them into the cranial cavity. The 

 orbitosphenoids are large, meeting at their inner edges at about a 

 right angle and uniting in a simple suture. The ethmoid is a ver}^ 

 small, thin, horizontal plate of bone, lying under the front of the 

 f rontals, between the extreme upper end of the prefrontals. Below it 

 is a wide open space between the prefrontals extending down to the 

 vomer. The prefrontals are nowhere in contact. They are not 

 pierced by the olfactory nerve, but deeply notched on their inner 

 edge. The vomer is supported anteriorl}" onl}" at the extreme upper 

 corners, Avhich touch the prefrontals. The nasals are very large 

 bones, broadly united to the frontals and to each other. They arch 

 widely over the anterior part of the cranium and inclose a chamber 

 behind them. 



FACE BONES. 



The hyomandibular has an undivided head. There is a small open- 

 ing between its lower anterior edge and the metapterygoid, Avhich 

 runs downward behind the latter, though no wing is developed in 

 front of it. There is a deep channel around the side of the preopercle 

 connecting with a similar one along the lower part of the mandible. 

 The angular is present. There is a small space between the upper 

 edge of the articular and the upper limb of the dentary. The mesop- 

 terygoid has a patch of teeth on its inner surface. The maxillary has 

 a large supplemental bone along the posterior half of its upper edge, 

 and extending down over its surface to its lower edge. The premaxil- 

 lary processes are rather long and stout. The suborbital ring is very 

 wide and deeply channeled, completely covering the cheek. There is 

 a prominent process on the inner surface of the preorbital, and a long 

 triangular process (the suborbital shelf), hooked downward, on the 

 second suborbital. Other face bones are essentially as in the Percoids. 



