122 ON EEMAINS OF jEPTOBMS IN THE BBITISH MUSEUM. [Feb. 6, 



result of convergence resulting from similar conditions of life, and 

 that though the great massiveness of the skeleton (pachyostosis) is 

 characteristic of both families, it is attamed in quite a different 

 manner in the two cases. This conclusion would certainly seem 

 to be supported by the bones here described. 



In the femora, for instance, apart from their great difference 

 of form, the large upper pneumatic foramen, the numerous smaller 

 ones opening into the popliteal fossa, and the great development 

 of the bony reticulum are characters entirely wanting in Dlnomis. 

 Such points of structure as these appear to be of more importance 

 in determining affinities than the mere external form of the bones, 

 which may be supposed to vary more readily with changes in the 

 conditions of life ; for it is difficult to understand how such differ- 

 ences of structure could arise in two closely related forms, since the 

 same end appears to be attained in the two cases in different ways. 

 The conclusion to be drawn from this is that the divergence 

 between the two families must have occurred before the character- 

 istic pachyostosis had been acquired. In their recent paper (4) 

 Milne-Edwards and Grandidier have given a brief description 

 of the skull, which, as far as it goes, does not seem to afford 

 much evidence in favour of the supposed close relationship with 

 Dinornis ; nevertheless, at the close of their communication the 

 authors, as in their former paper, assert their belief that there 

 is really such a relationship, and suggest the former existence 

 of a southern land-connection to account for it. Perhaps when 

 a complete description with figures of the skull, sternum, and 

 pectoral girdle have been published, it may be possible to arrive at 

 some definite conclusion concerning this interesting point. 



List of papers referred to. 



1. BiANCONi, G. G. — Numerous papers pubHshedin the ' Memorie 

 dell' Accademia delle Scienze dell' Istituto di Bologna' 

 between 1861 and 1873. 



3. BuRCKHARDT, R. — " TJeber JEpyornis." . Paliiontologische 

 Abhandlungen, Neue Folge, Bd. ii. Heft 2. Jena, 1893. 



3. Edwards, Alph. Milne-, et Ale. Grandidier. — " Nouvelles 



Observations sur les Caracteres zoologiques et les Affinites 

 naturelles de VjEpyomis de Madagascar." Annales des 

 Sciences naturelles (Zoologie), serie 5, vol. xii. Paris, 1869. 



4. Edwards, Alph. Milne-, et Ale. Grandidier. — "Observations 



sur Y^pyomis de Madagascar." Comptes Eendus de I'Acad. 

 d. Sci. t. cxviii. p. 122. Jan. 1894. Paris. 



5. FiJEBRiNGER, Max.— Untersuchuugen zur Morphologic und 



Systematik der Vogel. II. AUgemeiner Theil, pp. 1463-6, 

 Amsterdam, 1888. 



6. Geofprot St.-Hilaiee, Isidore. — " Note sur des ossements 



et des oeufs trouves a Madagascar dans des alluvions modernes, 

 et provenant d'un Oiseau gigantesque." Comptes Eendus de 

 I'Acad. d. Sci. t. xxxii. p. 101. Paris, 1851. 



