1922.] Recently published Ornithological Works. 739 



amis, a generic name which he gave to the Berlin specimen, 

 usually known as Ardueopteryx siemensi Dames (see Proc. 

 Zool. Soc. 1917, p. 5). The coracoid, which is short and 

 broad, is shown to be that of a ratite rather than of a cari- 

 nate bird, and is, moreover, not unlike the coracoid of some 

 reptiles. The pelvic bones remain separated by sutures, and 

 all take part in enclosing the perforate acetabulum. There 

 is a long pubic symphysis much like that seen in some 

 Dinosaurs. The only recent bird in which there is a pubic 

 symphysis is St7'Uthio, hut even there it is of quite a different 

 form. The second section of the paper is devoted to a detailed 

 account of the numerous differences between the two speci- 

 mens (London and Berlin), and their generic separation seems 

 fully justified. The author even states that they may have 

 belonged to ditferent families, a suggestion made many years 

 ago by Professor Seeley (Rept. British Assoc. York for 1881, 

 1882, p. G18). 



Petronievics furthermore institutes an elaborate compari- 

 son between the pelvis and shoulder-girdles of Archceojiteryx 

 and Archaornis and those of the various gi'oups of reptiles. 

 As a result of these comparisons he arrives at the following 

 conclusions : — 



1. ''The birds are undoubtedly derived from the reptiles.'" 



2. "The ancestors of the birds are to be sought among 

 the Lacertilia, or at least the birds and Lacertilia had 

 a common ancestor ; this conclusion seems to rest 

 mainly on the structure of the coracoid." 



3. "The similarity between birds aiul Dinosaurs is due to 



convergence." 



4. '^ Archaopteryx is more primitive than Archceornis in 

 the structure of its pelvis and shoulder-girdle. '^ 



5. '"' Archd'opteryx cither stands nearer the generalized 



type of bird from which both the Carinatae and Batitie 

 arose or closely represents that type, since, on the one 

 hand, it possesses the developed wings of a Carinate, 

 and, on the other, the primitive coracoid and probably 

 keelless sternum of the Katitc." Here, however, it 



