Gallino-Gralline Group of Birds. 431 



4. None of the vertebrae which precede the ankylosed sacral 

 vertebrae are ankylosed, 



5. The coracoids are furnished with subclavicular processes. 



6. The pelvis is not laterally compressed. 



7. The hallux is either absent or consists of only one 

 phalanx. 



8. They vary in the number of dorsal vertebrae which are 

 unfurnished with ventral processes, the Oceanitidae and the 

 Dioraedeidae having three, but the Procellariidae rarely having 

 any. 



Rather more than half the species possess basypterygoid 

 processes, but they are absent in the Diomedeidae, the Oceani- 

 tidae, and in the genus ProceUaria and one or two allied 

 genera. 



The 1st character is absolutely diagnostic. The combi- 

 nation of the 2nd, 3rd, and 4tli characters are diagnostic, 

 except that they do not exclude the Grallae. The addition 

 to this combination of the 8th character still leaves the 

 Oceanitidae and Diomedeidae undistinguished from the Oti- 

 didae. It is difficult to avoid coming to the conclusion that 

 the Tubinares are a highly specialized group, nearest related 

 to the once large, now small, group of the Grallae. 



Gavio-Limicol^. 



I have been unable to find any osteological characters to 

 separate the Gulls from the Plovers, except the presence in 

 the latter, and the absence in the former, of basipterygoid 

 processes. As this character is not constant in the Tubi- 

 nares, and occasionally breaks down in the Grallre, it must 

 be received with caution, or at least be regarded as of secon- 

 dary importance. The Gaviae are connected with the Linii- 

 colae by a series of intermediate genera : Dromas and Chionis 

 might be regarded as Gaviae, and Glareola, Cursorius, Plu- 

 vianus, and (Edicnemus as Limicolse, whilst Thinocorus might 

 be regarded as an archaic survivor of the common ancestors 

 of both ; but as basipterygoid processes are unknown in any 

 of these genera, if this character be taken as the test, they 

 must all be removed from the Limicolae to the Gaviae. It is 



SER. V. VOL. VI. 2h 



