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Show 148 PROF. W. H. FLOWER ON THE ELEPHANT SEAL. [Jan. 4, The dimension given above does not express the whole length of the largest skull, though it does of the smaller ones, as in the older animals the occipital ridges become so greatly developed as to project backwards beyond the condyles. This takes place to such an extent in the case of the new skull as to give an extreme length of 597 millimetres, or 23| inches. In very young skulls, on the other hand, the most posteriorly projecting part is the middle of the squama occipitis, at or above the upper margin of the foramen magnum. This expresses the preponderance of the brain-case over the other parts of the skull at this stage of development. In the next stage the growth of the condyles outruns that of the brain-case ; and finally the development of the great crests for muscular attachment give a very different general aspect to the cranium. The remaining principal dimensions of this skull are the following :- millim. Extreme width across zygomatic arches 384 Width between occipital crests 242 Greatest width of palate 185 Width of maxillae across middle of rostrum 176 Width between outer sides of base of upper canines 158 Width between apices of upper canines 120 W^idth between outer sides of base of upper lateral incisors 60 Width between outer sides of base of lower canines 93 Length of palate, from notch in middle line behind to incisor teeth 272 Length of ramus of lower jaw 375 Greatest width between coudyles of lower jaw 352 I have great hopes of obtaining, if not the whole skeleton, at least some of the principal bones belonging to the skull now described, as Mr. Mansel informs me that, after securing the head, he left the remainder of the body above high-water mark at the spot where it was killed. W e shall then have the means of verifying his estimate of 21 feet, which I presume includes the length of the hind feet or flippers, and which will probably be not far from the maximum to which the animal reaches. It is probable that, as in many of the Pinnipedia, and indeed in animals of almost all other groups, there is some variation in the size attained by adult specimens; and the head, especially of the males, continues to increase in magnitude some time after trie animal has apparently reached maturity, by the addition of bony outgrowths, ridges, and crests for the attachment of muscles, and by the enlargement of the alveolar portions of the jaws for the support of the increasing roots of the great canine teeth. But the statements of those voyagers who ascribe a length of 25 or even 30 feet to some individuals of this species must of course be taken with considerable reserve, and require to be verified by the accurate measurements of actual specimens. It would be strange if the natural tendency to |