400 Mr. R. Lydekker on 



nature, since the fossil remains of raptorial birds are in most 

 cases relatively much more rare than those of other groups. 



Steganopodes. — In the year 1857, the late M. Edouard 

 Lartet described the humerus of a large bird, remarkable for 

 its extraordinary length, which had been obtained fi'om the 

 Miocene of France, under the name of Pelagomis miocanus. 

 This extraordinary bone, which is considerably longer than 

 the humerus of the Albatross {Diomedea exulans), was re- 

 garded by its original describer as indicating a bird allied to 

 the group containing the Albatrosses. M. A. Milne-Edwards, 

 however, by whom the specimen was subsequently described 

 and figured, pointed out that it differed in toto from the 

 humerus of the Albatross, as was especially shown by the 

 relatively small expansion of its proximal extremity, the 

 slight development of the delto-pectoral crest, and, above all, 

 by the absence of the ectepicondylar process on the radial 

 side of the distal extremity, the presence of which is so 

 characteristic of this bone in all the Tubinares and their 

 allies. Moreover, since in all the features in which the 

 humerus of Pelagomis differed from the corresponding bone 

 of Diomedea, it resembled that of the Gannet {Sula), M. 

 Milne-Edwards came to the conclusion that it certainly indi- 

 cated a genus of Steganopodes more or less closely allied to 

 the Gannet. Indeed, this humerus, in spite of its enormous 

 length, evidently indicated a bird of comparatively weak 

 flight; and M. Milne-Edwards therefore felt himself justified 

 in saying that " it is probable that Pelagomis was a bird of 

 massive proportions, and much better adapted for swimming 

 than for flight,^' and concludes that its tarso-metatarsus must 

 have been as relatively short as in the Gannet. 



With the exception of another humerus subsequently found, 

 nothing more, so far as the writer is aware, is known of 

 Pelagomis. In the year 1877, however, Mr. Shrubsole 

 submitted to Sir R. Owen two associated broken bones of a 

 large bird from the London Clay of Sheppey, which were 

 described by the Professor in the ' Quart. Journ. Geol. Soc' 

 for the following year under the name of Argillornis longi- 

 pennis. These broken bones proved to be portions of the 



