404 Mr. R. Lydekker on 



members of that group in having no distinct temporal fossae. 

 In addition to the skull, the British Museum possesses the 

 proximal extremity of a left ulna, which may very probably 

 be referred to the present species, although, perhaps, not to 

 the same sex as the skull. This bone is very similar to the 

 larger ulna of Argillornis, and, if rightly referred to Odonto- 

 pteryx, clearly points to the Steganopodous affinities of that 

 genus. The proximal portion of a tarso-metatarsus from 

 Sheppey, recently presented to the national collection by Mr. 

 "W. H. Shrubsole, may likewise be provisionally assigned to 

 Odontopteryx, and, so far as its condition permits of forming 

 a judgment, appears to be of a Steganopodous type. It is 

 probable, however, that this tarso-metatarsus differed from 

 the corresponding bone of the existing representatives of the 

 group in the much smaller development of its talon (hypo- 

 tarsus) — a feature which appears to be characteristic of 

 many of the earlier birds. 



Herodiones. — The Herons and their allies present the 

 peculiar feature of the extensive overlapping of the distal 

 extremities of the two coracoids, the grooves in the sternum 

 for their reception likewise overlapping one another in a 

 similar manner. There is, indeed, a somewhat similar over- 

 lapping of the coracoids in the Flamingoes {Phoenicopterus) , 

 but in that genus the keel of the sternum is given off at a 

 lower level than in the Herons. Some of the characteristic 

 features of the tarso-metatarsus of the Herons have been 

 mentioned when treating of the birds of the superficial de- 

 posits. 



During the excavation of the tunnel of the North- Western 

 (then London and Birmingham) Railway through the London 

 Clay of Primrose Hill, there was discovered the sternum of 

 a bird of about the size of the Purple Heron, which presents 

 the overlapping of the coracoidal grooves and the relative 

 high position of the keel characteristic of the existing Herons. 

 This specimen, now in the British Museum, was described 

 and figured in Owen^s ' British Fossil Mammals and Birds ' 

 without any name; since, however, it clearly indicates a 

 distinct genus, the writer has proposed to designate the bird to 



I 



