of the Mccscarene Islands. 131 



which are destitute of spurs, there also exists a bony crest or 

 stay which unites the postero-iuterior margin of the bone witii 

 the heeh These characters are entirely wanting in the fossil 

 found in the Mare aux Songes. If we compare this meta- 

 tarsus with that of the waders, we find that its relative pro- 

 portions, as well as its anatomical peculiarities, separate it 

 from that of the CiconidaJ, Gruid^e, Ardeidaj, Totanidte, and 

 Bustards; but we find in it great analogies with the foot-bone 

 of certain representatives of the family llallidje, although it 

 differs much from the typical form in this group. But it is to 

 be remarked that in proportion as these birds are constructed 

 for walking, their metatarsus acquires more and more the dis- 

 tinctive characters of that of Aj}hanaj)ter^x : thus in passing 

 successively from the Coots to the Rails, to Tribonyx and to 

 Ocydromus^ we insensibly arrive at the form which is pre- 

 sented by oiu- fossil, and which, at the first glance, would ap- 

 pear to be quite special. 



In the same deposit with this lower mandible and tarso- 

 metatarsal several tibise have been discovered, which seem to 

 be referable to the same bird ; for the study of the peculiari- 

 ties which they present leads to the same result as the exami- 

 nation that I have just made of the osteological characters of 

 the foot-bone. 



All these anatomical facts prove, it seems to me, that Aphan- 

 apteryx forms a peculiar generic division side by side with 

 Ocydromiis. It must be regarded as one of those transition 

 forms which are so remarkable in the animal kingdom ; it is 

 a rail, the organization of which has adapted itself to an 

 essentially terrestrial existence. 



We see, from the figure the knowledge of which we owe to 

 M. von Frauenfeld, that the featliers of this bird were too 

 light and possessed too little resistance to have been capable 

 of serving it for flight, and moreover the wings were rudimen- 

 tary ; the feet, on the contrary, presented considerable strengtli, 

 but they are not very long, and the toes are less elongated 

 than is usual in this family. This would lead us to think 

 that this species had less aquatic habits than most of the 

 Rallidai ; nevertheless the [hind] toe is very long, as in birds 

 which frequent muddy places where the soil has but little 

 consistency, whilst among the true runners it disappears more 

 or less completely, in order to diminish the weight at the ex- 

 tremity of the ai-m of the lever fonned by the foot. 



The recent destruction of the Aphanapteryx can only be 

 ascribed to man or to the animals which he brought in his 

 train ; and it is interesting to remark that tliis species, which 

 inhabited the Mascarene Islands at a period so nearly ap- 



