6 



THE VOYAGE OF H.M.S. CHALLENGER. 



the Elephant Seal obtained from the Falkland Islands, and, for convenience of reference, 

 have included in the table the measurements of his specimen. 



From this table it will be seen that none of these skulls equalled in length the 

 Falkland Island specimen, or indeed two other large skulls referred to in Professor 

 Flower's table on p. 147 of his memoir, but that they closely approached in length the 

 skull in the Berlin Museum obtained in Kerguelen Island by the German Transit of Venus 

 expedition. In their other dimensions also they were much smaller than the skull from 

 the Falkland Islands above referred to, which is much the largest specimen that has yet 

 been measured. The very material difference between the dimensions of the male skulls 

 and the largest female will at once be recognised. It will be of importance therefore to 

 determine, if possible, whether this difference is sexual or merely due to a difference in 

 relative age. The female skull is, I believe, to be regarded as approaching adult, for the 

 occipito-sphenoidal synchondrosis was obliterated, except for a faint trace on the surface 

 of the bone on each side, and the junction between the pre- and post-sphenoids was only 

 indicated by a surface mark. But it should be stated that in the cervical vertebra? 

 which accompanied this skull the plate-like epiphyses of the bodies were not ankylosed. 

 In the female skull next in size to the above, the condylo-premaxillary length of which 

 was 274 mm., both the basi-cranial synchondroses were unossified, though the interval 

 between them was narrow. 



Table I. — Crania of Elephant Seal. 



Length from front of premaxilla to occipital condyle, 

 ,, ,, to occipital crest, 



Extreme interzygomatic width, .... 



Extreme width between occipital crests, . 



Greatest width at posterior edge of external meatus, 



Greatest width of palate, ..... 



Width of maxilla across middle of rostrum, 



Width between outer sides of base of upper canines, 



, , , , upper lateral incisors, 



,, „ lower canines, 



Length of palate from mesial notch behind to incisor teeth, 



Height of skull from basion to middle of occipital crest, . 



Smallest inter-frontal width in plane of upper surface, 



Length of nasals, ...... 



Greatest width of anterior nares, .... 



Vertical diameter of mea-ethmoid at anterior nares. 



From anteroinferior angle of mes-ethmoid to central incisor, 



Greatest length of mandible, .... 



Greatest width at condyles of lower jaw, . 



In Dr. Scott's male the occipito-sphenoidal synchondrosis was obliterated mesially, 

 but on each side a gap about 1 mm. wide separated the two bones ; the synchondrosis 

 between the pre- and post-sphenoids was, however, open both mesially and laterally. 



