THE 



AMERICAN NATURALIST 



Vol. XL Juhj, 1906 No. 475 



ADAPTIVE MODIFICATIONS OF OCCIPrFAL 

 COXDVLKS IN MAMMALIA 



CHARLES S. MEAD 



Historical 



A XU3MBER of papers have been written on the occipital condyles 

 but they deal with them from either an ontogenetic or a phyloge- 

 netic standpoint. Osborn (:00) has shown that certain of the 

 mammals, such as Tachyglossus (Echidna) and Cercoleptes, pos- 

 sess but a single tripartite condyle continuous across the me(Han 



condyles widely separated and tliat bciwccn tlu'sc two i'xtrciiic> 



reduction of the median l>a-^io(cipiial eleuient and the expansion 

 of the lateral exoccij)ital clenuMUs."' 



the various vertebrates, comes to the conclusion that "the oriuinal 

 craniocervical j(Mnt nuist have been a paired one, fonncd l)y rlic 

 lateral occipitals witli their more or less serially honioh.U'ons |,art,-. 



