REPORT ON THE SEALS. Gl 



larger articulation with nasal proportionally than in the other species. Antorbital 

 processes are faint tubercles. Zygomatic arches comparatively flattened, their greatest 

 transverse diameter at posterior part of arch, and the transverse diameter of cranium 

 behind external meatus greater than interzygomatic diameter. Malar bone short, only 

 about equal in length to the same bone in Phoca hispida. Hard palate truncated behind 

 and reaching close to the hamulars ; posterior border of vomer almost entirely concealed 

 and extending very obliquely forwards to join the vomerine crest of the superior 

 maxilla. Tympanic bulla not so swollen as in the other species and somewhat rougher 

 on inferior surface. Foramen lacerum posterius small, basi-occipital not perforated 

 mesially, par-occipital s distinct. The floor of the orbit not so oblique as in the other 

 species of Phoca, but approximating more nearly to the vertical. Post-canines with 

 distinct intervals between, and not very strongly implanted. Subcondyloid process of 

 mandible large, triangular, deeply incurved, and continued by a ridge into the tubercle 

 at the angle of the jaw ; lower border of body a little incurved and concave in its 

 general outline. Coronoid process shorter and less pointed than in the other species, 

 and the sigmoid notch more shallow. 



A comparison of the cranial characters of Phoca barbata with those of the three 

 other species of the genus Phoca, shows that it differs more from them than they do 

 from each other. These differences are especially seen in the lower jaw as just stated, 

 in the flattening of the zygomatic arches, so that the cranial breadth is greater than the 

 interzygomatic diameter, in the more vertical direction of the floor of the orbit, and in 

 the very pronounced ridge along the line of the squamous suture. It has been pointed 

 out by previous writers (Gill, Allen) that Phoca barbata differs from the other species 

 of Phoca in having a broader muzzle, in the middle digit of- the manus being the longest 

 instead of the digits slightly decreasing in length from 1st to 5th, and in possessing 

 four and not two mammae, and on these differences Gill has established for it the 

 genus Erignathus. To these external differences may now be added those cranial 

 differences which I have just described, so that from the point of view of those zoologists 

 who are in favour of the multiplication of genera, additional data are given for separating 

 it from the genus Phoca and calling it Erignathus barbatus. 



I have not seen any specimens of the Seals which have been named Phoca caspica, 

 Phoca siberica, and Phoca equestris {Histriop)hocafasciata). 



Halichcerus, Nilsson. 



Infraorbital foramen does not open into anterior part of floor of orbit but below it, 

 for the floor of orbit does not form a continuous slope with the posterior border of the 

 zygomatic root of maxilla, but is separated from it by a deep vertical surface. Anterior 

 nares high and capacious. Post-canines each with a large, conical, simple cusp ; 



