378 



ME, E. E. BEDDAED ON THE 



III. Osteology. 



I have been able, through the kindness of Mr. Thomas, to study the large collection 

 of skulls of Sea-Lions which are in the Natural History Museum. I do not, however, 

 consider it necessary to illustrate the skull of 0. hookeri by figures, as this has been 

 already done by Mr. Clark in his paper l , and also by Dr. Gray ; these zoologists have, 

 between them, figured the skulls of both sexes. Mr. Clark adds to his figures a some- 

 what detailed description of the cranial characters of 0. hookeri ; its salient points 

 have also been noted by Gray. 



The following are the principal characters (partly noted here for the first time, 

 partly already recorded) which distinguish the skull of 0. hookeri from that of 0. jubata. 

 They are arranged for convenience' sake in a tabular form : — 



Otaria jubata. 



1. Palate excavated behind. 



2. Posterior nares on a level with the arti- 

 culation of squamosal and jugal. 



3. Muzzle truncated. 



4. Pterygoids massive and somewhat trian- 

 gular in form, the apex pointing downwards. 



5. Palatal bones with a perfectly straight 

 posterior margin. 



6. Anterior margin of nasals on a line with 

 zygoma and suborbital foramen. 



Otaria hookeri. 



1. Palate not excavated behind. 



2. Posterior nares on a level with middle of 

 jugal. 



3. Muzzle more pointed. 



4. Pterygoids ending in a hooked process, as 

 in most of the Mammalia. 



5. Palatal bones with convex posterior 

 margin. 



6. Line drawn through nasals at right angles 

 to long axis of skull falls much anterior to this 

 point. 



This tabular statement does not take any account of numbers of minute points of 

 difference, but it contains, I believe, the principal distinctive features, which are by no 

 means few. 



As to these points, I have compared the skulls of 0. jiibata and 0. hookeri with those 

 of the other species contained in the National Collection, viz. those labelled 0. stelleri, 

 0. ursina, 0. gillespii, 0. pusilla, 0. nigrescens, 0. cinerea, 0. forsteri. I find that the 

 skull of 0. jubata differs from all of these in exactly the same points that I have 

 already referred to as distinguishing that species from 0. hookeri ; likewise that all the 

 other species, 0. stelleri &c, though doubtless presenting certain points of difference 

 among themselves, yet agree in the structural features to which attention has been 

 already called in the tabular statement above given. 



These characters may not be important ones, but, if not, they are at least numerous, 

 and must thei*efore be considered as being collectively of some importance. Their impor- 

 tance is also clearly increased by the fact that they absolutely concur with other struc- 

 tural features to which particular attention has been directed in the previous portion 

 1 " On the Eared Seals of the Auckland Islands," P. Z. S. 1873, p. 750. 



