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Show 1871.] PROF. FLOWER ON PHOCA HISPIDA. 511 Tt must first be mentioned that it is that of a very aged animal, as shown by the condition of the cranial sutures and the teeth. Of the latter some had been lost during life, and others after the preparation of the skull; and all those that remain are worn down nearly to the level of the alveolar border, so that they are of little use for identification. As far, however, as their characters serve, they agree with those of other specimens of P. hispida with which I have compared them, being rather smaller than those of P. vitulina, and having the long diameter of the molars in a line with the alveolar border, and not oblique, as is almost always the case with the latter. The deep angular emargination of the hinder border of the bony palate at once distinguishes this skull from that of either P. barbata or P. grcenlandica; so that P. vitulina is the only one with which it could be confounded. It is distinguished from this species :- 1st. By its small size ; for though Seals have a considerable range of variation in this respect, all the perfectly adult examples of vitulina I have met with are considerably larger than the present specimen, ranging from 7'7 inches (196 millim.) to 8*5 inches (216 millim.). 2nd. By the narrowness of the upper surface of the skull between the orbits, and also of the nasal bones. Different specimens of P. vitulina vary much in this respect, but they are always broader in this region than P. hispida. 3rd. By the presence of a rudimentary anteorbital process on the maxillary bone, which is always absent in P. vitulina. 4th. By the pointed form of the upper end of the ascending process of the prsemaxilla, which is in contact for a considerable space with the nasal-whereas in P. vitulina this process is usually more or less truncated above, and is completely separated from or only just touches (at one point) the nasal. Both P. barbata and P. grcenlandica resemble P. hispida in this character. 5th. By the posterior palatine foramen being situated on or behind the maxillo-palatine suture. In P. vitulina it is placed in the maxillary bone altogether in front of the suture. This and the last are important diagnostic characters, being constant and readily recognized. 6th. By the wide interval on the upper surface of the cranium between the ridges which bound the temporal fossa, whereas in old specimens of P. vitulina these ridges meet at the vertex. 7th. By the larger size of the unossified spaces in the base of the skull lying to the inner side of the auditory bullae. 8th. By the comparative shallowness (vertically) of the hinder portion of the ramus of the mandible, occasioned by the smaller development of the region of the angle, and especially of the anterior margin of the coronoid process, which is altogether weaker than in P. vitulina. 9th. By the form of the inferior margin of the ramus of the mandible, which in the present species (as in P. barbata and grcenlandica) has a conspicuous expansion inwards a short distance behind the symphysis, which causes the edges of the rami to continue more or less approximated for nearly half the length of the lower border |