588 ON THE VARIATION OF THE SEA-ELEP HANTS. 



condyles of his " crosetensis " are " extremely narrow." To judge 

 from his figure (I. c. p. 605) the condyles of the Crozet skull appear 

 to be only about 20 per cent, of the basal length of the skull, 

 although the latter measurement is said to be " 16 - 5 ins." or 

 412 mm. According to the condition observed in the material 

 from South Georgia, the condyles of such a small skull ought to 

 have been something about 28 per cent, of the basal length. It is 

 possible that this characteristic together with others — but hardly 

 those discussed above — might prove that a racial difference exists 

 in the geographic group represented by the' Crozet skull. It is, 

 however, difficult to base any opinion about this on a single skull 

 when these animals have proved so extremely variable in their 

 skull characters. Unfortunately, Turner has not communicated 

 any measurements of the condyles of his skulls from Heard Island 

 and Kerguelen Island. 



The Sea-Elephant skulls from South Georgia show a quite 

 irregular variation in many other respects than those already 

 mentioned. The general shape of the nasals is, for instance, very 

 variable as the accompanying four figures (text-fig. 56 A-D, 

 p. 587) prove. The dimensions are also extremely different in 

 different specimens with regard to length as well as to width, as 

 may be seen from the table of measurements. The mesethmoid 

 reaches the upper surface of the skull and fills up the mesial 

 anterior notch between the nasals, where it expands more or less 

 in different specimens as the figures of the nasals show. By this 

 a continued growth forward and ossification of the nasals in the 

 mesial line is made impossible, but on either side of the meseth- 

 moideum there is free space enough for such a growth and this 

 might contribute to the irregular shape of the nasals. 



The exceedingly great variation of the Sea-Elephant skulls 

 appears to be fully proved by these notes, and it must certainly be 

 regarded as a very interesting fact. This great variation is partly 

 explained by the general rule that large mammals, the growth of 

 which is continued through a long period of years, each of which 

 contains different seasons with different conditions of life, are more 

 apt to vary than such as conclude their growth within one year. 

 Another factor which also may be of some impoi-tance in this 

 connection is that the Sea-Elephants originally had hardly any 

 dangerous foes which could influence a natural selection. Now, 

 however, these very interesting and completely harmless sea- 

 monsters have been unfortunate enough to provoke the most 

 dangerous of all foes — the greediness of man ; and by this they are 

 threatened with extinction even in the few remote places where 

 they may still exist in limited numbers. Indeed, the Southern 

 Sea-Elephant is doomed to share the sad fate of its Californian 

 relative if speedy measures are not taken for its protection. The 

 hope of zoologists and all friends of living nature is that \he, 

 the Government of Great Britain may give this protection which 

 is so sorely needed. 



