1885.] DR. ST. G. MIVART ON THE PINNIPEDIA. 487 



process, behind which the bone is rounded. The stylomastoid fora- 

 men Ucs in a deep groove which divides the mastoid from the bulla. 

 The meatus auditorius externus is produced outwards, but its lower 

 lip inclines so much upwards posteriorly that the aperture is made 

 to look more forwards than upwards, and the outer end of the lip 

 may be produced a little forwards in front of the aperture. There 

 is a postglenoid foramen. The posterior palatiue foramina are 

 situated behind the middle of the palate. The pterygoid has a 

 distinct hamular process. The basis cranii has a surface bent convex 

 downwards between the occipital foramen and the presphenoid. 

 Venous canals traverse the inside of the exoccipitals and open on the 

 inner side of either occipital condyle. The mandible has a distinct 

 subangular process, and the angle is pressed up very near the con- 

 dyle. The symphysis may be long or short. 



Dentition : — I. I C. \, P. j, M. j=34. 



Molars, except the lirst, with two roots. Each upper molar has a 

 principal cusp with one or two accessory cusps behind, and some- 

 times one in front of it. The lower molars have each a principal 

 cusp with one, sometimes two, accessory cusps in front of it, and 

 generally two behind it. 



In P. vitulina the hinder margin of the palate is V-shaped, the 

 apex being forwards. The suture between the palatines and maxdlte 

 forms a straight transverse line. The teeth are rather large and 

 raulticuspidate. 



In P. grcenlandica the palate has a straight, transverse, hinder 

 margin. There is sometimes a distinct pterygoid fossa. The par- 

 occipital process may form a marked, nipple-like projection. The 

 teeth are more sim])le than in P. vitulina. 



In P. barbata the maxilla has a swollen outer surface ; venous 

 canals open inside the upper margin of the foramen magnum, and a 

 curious ridge runs downwards and forwards across the squamosal and 

 parallel with the hinder root of the zygoma. The meatus auditorius 

 externus looks mainly upwards. The paroccipital process is rather 

 prominent. The palate extends far back, and has an evenly concave 

 hinder margin. The two parietals form a small wedge-shaped pro- 

 cess which advances between the hinder margins of the two frontals. 



Halichoerus^. — This genus contains but oue species, H. gnjphus, 

 which inhabits the coasts of Scandinavia and the British Isles. Its 

 palms and soles are hairy, and it has five well-developed claws on 

 each foot, those of the manus being the broader and more curved. 

 There are 15 dorsal, 5 lumbar, 4 sacral, and about 14 caudal 

 vertebrae. 



In the skull thesame characters are found as those already attributed 

 to Phoca, except that there is a more decided defect of ossification 

 between the ali- and basisphenoids and the pterygoid. Moreover 

 the palatiue foramina are much behind the middle of the palate. 



1 Fabric. Skrivt. af Naturb. Selsk. i. p. 167, tab. 13. fig. 4 ; Nilsson, Vet. 

 Atad. Haudl. p. 377, tab. 34. figs. 1 & 2 ; Bell, Brit. Quad. p. 278 ; Gray, Cat. 

 Brit. Mils. p. 33 ; Schrebftr, Fortgesetzt Wagner, vii. p. 12 ; De Blainville, 

 Osteogr. Phoca ; Allen, North Amer. Piun. p. 682. 



32* 



