1868.] 



PROF. HUXLEY ON THE ALECTOROMORI'H^. 



311 



and their extension outwards beneath the tympanum, Opisthocoinus 

 resembles the Alectoromorj)h(B. 



Fig. 16. 



The skull of O^isthocomus cristatus, viewed from below, with the palatine buncs 



enlarged, from another specimen. 



Vo. Vomer. PL Palatine bones. Ft. Pterygoid. 



Upon the whole, then, I think it may be said that, in skull, verte- 

 bral column, pectoral arch, and fore limb (except, perhaps, the 

 scapula and the humerus), pelvis, and hind limb, Opistliocouins 

 resembles the ordinary Gallinaceous birds and the Pigeons more 

 than it does any others, and that when it diverges from them it is 

 either sui generis or approaches the MusophagidcB, 



I propose to consider it as the type and sole member of a group 

 which may be termed Heteromorph^. 



IV. Taxonomic conclusions. 



The only other birds, in addition to those which have now been 

 mentioned, which come into direct relation with the Alecforoinorphce 

 are the TinamomorphcB, Chenomorphce, and, perhaps, the Birds of 

 prey ; but I do not purpose to enter upon the discussion of the 

 affinities of these groups at present. 



To sum up the taxonomic results of the preceding (somewhat 

 lengthy) discussion of the characters of the Alectoromorphce, Ptero- 

 cloinorphee, Tui'niciniorp/ice, and Heteromorphce, I think it can be 

 proved that the Alectoromorphce, the I'teroclomorpha, and the Pe- 

 risteromorphoB form an extremely natural series ; and if the words 

 "Gallince" and "Gallinaceous" had not been already used in so 

 many senses, I should propose to employ them to designate it. As 

 matters stand, there will be less chance of confusion and misundcr- 



