524 ON A NKW FOSSIL BIRD. 



and, although the anterior angle of the keel widens out and was 

 in contact with the furcula, there was no definite articulation 

 between the two. In other members of the group, however, 

 some of these characters are present. Thus, in Procellaria the 

 dorsal fossa is present, and in the Diving Petrels (Pelecanoides) 

 the furcula has a definite articulation with the anterior end of 

 the sternum, and it seems possible that this articulation may in 

 some way be connected with the diving-habit, since it is well 

 developed in Sula and Phcdacrocorax, both notable divers ; on the 

 other hand, Fregata, in which the furcula is actually fused with 

 the sternum, seems never to dive. Comparison of the fossil with 

 the sterna of Sula and Phcdacrocorax in other respects, shows 

 thni. in the depth and shortness of the keel and in the form and 

 position of the coracoid grooves they are somewhat similar. On 

 the other hand, the keel projects much more forwards, the spina 

 externa is thin and compressed, there is no dorsal fossa, and the 

 position of the intermuscular ridges on the keel is different. 



Comparison with the sterna of other groups of birds has led 

 to no satisfactory results. In the case of some of the Storks 

 (e. g. Argala) the furcula has an extensive union with the anterior 

 angle of the keel, but in other respects the form of the sternum 

 ditiers from the fossil. The sterna of the Penguins and Auks 

 also differ widely, the keel being very long and there being no 

 union with the furcula. On the whole, we may conclude that 

 Gigantornis was most nearly related to the Tubinares and 

 Steganopodes, perhaps approaching the former more nearly, and 

 it may, indeed, be the representative of an extinct group more or 

 less intermediate between these two. 



Further collections from the same locality are greatly to be 

 desired, since nearly all the few specimens hitherto obtained 

 represent forms new to science and of the highest interest. 



Some dimensions (in millimetres) of the fossil are : — 



Length of the portion of body preserved 136 



Greatest depth from anterior upper border of 



body to antero-inferior angle of keel 140 



Distance from anterior angle of coracoid groove 



to antero-inferior angle of keel 127 



Length of coracoid groove (f'PP-) 77 



Distance between anterior ends of coracoid 



grooves 18 



Depth of surface for furcula ('^PP-) 45 



Greatest width of surface for furcula 26 



Thickness of lower border of keel at level of 



hinder end of coracoid grooves 12 



Text-fig. 4 represents the sternum of a large Wandering 

 Albatross {Diomedea exulans), which in the flesh measured 

 10 ft. 8 in. from tip to tip of the wings; the fossil sternum, so 

 far as measurements are possible, seems to have been about twice 

 as large. 



