490 DR. ST. G. MIVART ON THE PINNIPEDIA. [^Ifl}' 19» 



addition to this, however, there is a faint trace of a frontal post- 

 orbital process. The anterior nares do not extend far backward?. 

 The palate is prolonged backwards behind the last molars, and its 

 hinder margin is slightly concave. The palfitine foramina open on 

 its hinder half. There is hardly any true paroccipital process, but, 

 as in the last-noticed genus, a vertical ridge near it projects back- 

 wards and away from the bulla. The mastoid is prominent, and its 

 prominence is continuous with that of the squamosal above the ex- 

 ternal auditory meatus, immediately above which opening is a great 

 antero-posteriorly extending bony swollen prominence. The meatus 

 opens between the outwardly projecting mastoid and the postglenoid 

 process, so that practically its lateral walls, but not its floor, are 

 prolonged outwards. There is a chink-like postglenoid foramen. 

 The basis cranii is always level, but slightly convex antero-posteriorly. 

 The mandible has no subangular process, but in the place where it 

 should be the bone is rounded. The coronoid is pointed, but small 

 and low, hardly rising above the condyle. The maxilla develops a 

 preorbital process. The symphysis is not prolonged. 

 Dentition :— I. ':, C. \, P. 1 M. i=32. 



The molars are very small, and have pointed, recurved crowns, 

 mostly with a marked posterior accessory cusp and sometimes with 

 one in front also. 



Moimchus^. — This genus, of one species from the ^Mediterranean 

 and Black Seas and the Atlantic Ocean about jNIadeira and the 

 Canary Isles, resembles the three preceding genera in having the 

 nails of the hind feet rudimentary, and the first and fifth toes 

 greatly longer than the others. The nails on the fore feet are also 

 rudimentary in this genus. 



There are 1.5 dorsal, b lumbar, 2 saci'al, and 11 caudal vertebrae. 



The skull iii its main characters resembles that of Phoca. The 

 crista galli and cerebellar fossa of the petrosal are rather larger. The 

 condyloid foramen is distinct, and placed midway between the 

 condyle and the foramen lacerum posterius. There is a distinct 

 preorbital process on the front rim of the orbit and developed from 

 the maxilla. The nasals are not anchylosed together, and the pre- 

 maxillse ascend to meet them. The palate is concave behind, and its 

 concave border is medianly notched. I have observed no defects of 

 ossification in the basi- or exoccipitals, hut (as in P. barbata) a 

 venous channel traverses the supraoccipital opening hy transverse 

 apertures above the foramen mttgnum and inside its margin. There 

 is a very large aperture on either side of the basis cranii bounded by 



^ Plwca monachus. Hermann, Beschaft. d. Berlin. Gesell. natiir. Freunde, iy. 



1779, p. 456, pi. 12, 13. 

 Plwquc a ventre hlanc. BufTon, Hist. Kat. Supp. vi. pi. 44; Cmier, Oss. 



Fobs. Atlas, vol. ii. pi. 218. 

 Monachus mediterranctis, Nilsson, Kong. Yet.-Akad. Handl. Stockbolm 



(1807). p. 235. 

 Leptonyx monachus, Scbreber's Fortg. Wagner, vii. p. 40. 

 Monachus albivcnfer, Gray. Cat. Seals Brit. Miis. (1806) p. 17; Allen, N. 



Auier. Pinnipeds, ]3. 465. 



