REPOKT ON THE SEALS. 33 



posterior border of the hard palate. In the young Falkland Island male the hard 

 palate differed in some respects from the adult; it had scarcely any concavity in its 

 posterior part, but anteriorly it was somewhat hollowed out ; the anterior part of the 

 palato-maxillary suture was opposite the penultimate molars ; the length of the palatal 

 surface of the palate bone was equal to the length from the palato-maxillary suture to 

 the incisive canal ; the widest part of the hard palate was immediately behind the last 

 molars. The posterior edge of the hard palate and the posterior nares in the two large 

 skulls were in the same transverse plane as the anterior border of the glenoid fossa, but 

 in the smaller adults they were a little anterior to that plane, and more so in the 

 young skull from Stanley. The hamular processes were curved and projected down- 

 wards, inwards, and then outwards. 



The great elongation of the palate in Otaria juhata is therefore due to the remarkable 

 antero-posterior diameter of the palatal plate of the palate bone, which completely con- 

 cealed both the sphenoidal articulation and the posterior border of the vomer, the latter 

 of which was falciform, and did not articulate with the palate, but passed forwards to 

 reach the vomerine crest of the superior maxilla. As the hard palate was covered by the 

 mucous membrane when the skull reached me, I took the opportunity of examining it 

 when softened prior to its removal. This membrane possessed numerous short papillae, 

 which, in the part of the palate situated between the molar teeth , were arranged in seven 

 low ridges, which were not quite transverse, but with a slight inclination backwards. 

 Between and in front of these rows similar dwarf papillae were scattered over tbe 

 mucous surface, but behind the last molars the membrane was smooth. 



All the crania possessed alisphenoid canals and mastoid processes. In all, the 

 tympanic bulla had a process projecting vertically downwards from the inferior surface. 

 In the larger adults it was thick and truncated, in the smaller adults it formed a sharp 

 ridge ; in the young male, although the ridge did not project so much as in the smaller 

 adults, it was quite as thick. The tympanic cavity was opened into in the Maldonado 

 specimen, and consisted of a large chamber, dilated below, which suddenly narrowed as 

 it ascended to the outer side of the petrous-temporal. The carotid canal opened within 

 the boundary of the jugular foramen. The occipital condyles were not continuous 

 anteriorly in the adults but separated by a definite interval, and their inner borders in 

 front lay in a plane running almost directly from before backwards; in the young skull, 

 however, the condyles were continued into each other in front, and the cartilage was 

 prolonged from one to the other. No supra-occipital foramen was visible either at 

 the foramen magnum or below the occipital crest. The inferior surface of the basi- 

 occipital had in the four adult crania an elevated ridge running antero-posteriorly, and 

 there was no mesial perforation in any of the skulls. The carotid canal opened imme- 

 diately within the boundary of the jugular foramen. The par-occipitals were stunted. 



The skulls from the Falkland Islands were the only specimens wh ich possessed a lower 



(ZOOL. CHALL. EXP.— PART LXVIII. — 1887.) Y yj 5 



