vol. 50.] fauna from the ightham fissure. 191 



Aves. 



The remains of Birds in this fissure are comparatively rare, and, 

 although some eight different forms have been recognized, only one 

 or two of them can be said to have been satisfactorily determined ; 

 they have been carefully compared with a number of recent skeletons, 

 and the names given below are believed to be correct, but the small 

 passerine birds are, in many cases, so much alike in their osteology, 

 that it is difficult to distinguish their bones, and the want of 

 skeletons for comparison prevents some of the other remains from 

 being definitely named. All the forms of birds alluded to in this 

 paper have a wide distribution, being found throughout the greater 

 part of Europe and Asia, extending northward to or beyond the 

 Arctic Circle, and southward to Northern Africa. 



Turdus musicus 1 (Song-Thrush.) — The proximal half of a 

 humerus, somewhat stouter than that of a lark and agreeing with 

 that of a song-thrush, is all that can be referred to this species. 



Scuvicola (Etianthe? (Wheatear.) PI. X. figs. 13, 14. — A humerus 

 and two metacarpals are provisionally placed in this species. 



Motacilla ? (Wagtail.) — Two ulnae seem to belong to either the 

 pied or the white wagtail. 



Anthus pratensis ? (Meadow-Pipit or Titlark.) — A single cora- 

 coid seems to agree most nearly with this species. 



Alauda arvensis. (Skylark.) PL X. figs. 10-12. — A humerus 

 and three metacarpals are referred to this species. The same bones 

 of the song-thrush are very similar in form and size to those of the 

 skylark, but the humerus of the former is a trifle stouter, and the 

 united metacarpals have a shorter opening left between them than 

 they have in the latter. With these bones are associated a part of 

 a tibia and two metatarsals. Two recent skeletons of this species 

 which I have in my possession differ markedly in size, especially 

 as regards their metatarsals ; and the two fossil examples of this 

 bone differ in a similar manner. 



Buteo ? (Buzzard?) PL X. fig. 18. — The greater part of a tarso- 

 metatarsus of a large raptorial bird I am unable at present to 

 identify with certainty. In general form it is like that of the 

 common buzzard, though it is not only larger, but has the proximal 

 part broader. Most probably it will prove to belong to the 

 somewhat larger Buteo lagopus, but I have been unable to obtain a 

 skeleton of that species for comparison. 



Anas boscas ? (Duck.) PL X. figs. 1 6, 17. — Two humeri agreeing 

 very closely with the same bones of the common duck are provi- 

 sionally placed in this species ; and with them are associated for the 

 present two ulnae, which, being rather too large proportionately for 

 the humeri, may represent another species. Three other fragments 



