ANOMALOGONAT^ - 167 



aEoup ORNITHUR/E 

 ANOMALOGONATiE ' 



Definition. — Generally quinoubital. Ambiens and accessory femoro- 

 caudal always absent ; biceps slip rarely present. Cervical 

 vertebree, 13-15. Atlas generally perforated by odontoid process. 

 Skull holorhinal. 



This group of birds is equivalent to the similarly named 

 group of Gaeeod, with the sole addition of the Striges. The 

 total absence of the amhiens, even of all traces of that muscle 

 (see p. 95), is to my mind a sufficient reason for bracketing 

 together all these birds. I am of opinion that the ambiens 

 is not degenerate in them, but that it has not yet appeared.^ 

 It must be admitted that there are not many other charac- 

 ters that run through the whole group. There are, never- 

 theless, certain peculiarities of structure that are confined or 

 nearly confined to this group. Thus, with the sole exception 

 of the parrots, a forked manubrium sterni is a peculiarity of 

 the AnomalogonatsB ; so too, with the same exception, is the 

 presence of a cucullaris propatagialis. Again, it is only here 

 and in the parrots that the syrinx has so complicated a 

 musculature. The very prevalent shortness of the intestine 

 is a fact (not, it is true, without exceptions) not to be ignored 

 in considering the claims of this group to existence. The 

 feet are nearly always anisodactyle or zygodactyle, there 

 being but few other birds not referable to this group in which 

 that structure of foot is to be found ; and those groups will 

 be treated of later as possible alliesW the present. Powder- 

 down patches are exceedingly rare in this group, and but 

 few possess the expansor secundariorum. 



I allow nineteen separate families of this group (whose 

 main characters are given in the table), of which some may 

 be united more closely than others. 



' Seebohm, ' An Attempt to diagnose the Pico-Passerine Group of Birds,' &c.. 

 Ibis, 1890, p. 29. 



'' A case which appears to contradict this statement is dealt with on p. 163. 



