430 Mr. H. Seebohm on the 



5. The horny covering of the nostrils is not tubular. 



6. They have no basipterygoid processes. 



The schizorliinal Grallse agree with all these characters 

 except the 4th. 



The Grail se vary exceedingly in the number of ankyloscd 

 vertebrse in front of the sacrum, and in the number of dorsal 

 vertebrae which are furnished with ventral processes. Most 

 of them have a small hallux, but the Otididse have none, and 

 the Opisthocomi and Mesitidse have a large one, like the 

 Columbae and some of the Gallinse (Cracidse and Mega- 

 podidse). 



The 6th character is not a very safe one. I have seen ex- 

 amples of one species of Grus, and of more than one species 

 of Otis, in which, for some inexplicable reason (if we call it 

 atavism it looks less like accident), the basipterygoid pro- 

 cesses have become ossified, instead of being absorbed during 

 the progress from youth to maturity. 



The holorhinal Grallse may be diagnosed by their combi- 

 nation of the 1st, 2nd, 3rd, 4th, and 5th characters. The 

 schizorliinal Grallce may be diagnosed by the same combi- 

 nation, after the necessary alteration of the 4th character has 

 been made. 



If osteological characters have the taxonomic value which 

 they are supposed to possess, the Tubinares appear to be the 

 nearest allies of the Grallae. 



Tubinares. 



The Petrels possess in their tubular nostrils a character 

 which distinguishes them from all their allies ; and although 

 this feature is confined to the horny covering of the bill, it 

 simplifies the diagnosis of the group so much, that I have 

 ventured to include it as one of their osteological characters. 

 These are as follows : — 



1. The external nostrils are produced into tubes. 



3. In the articulation of their dorsal vertebrae they are 

 heteroccelous. 



3. In the bifurcation of their nasals they are holorhinal. 



