330 DR. GADOW ON THE ANATOMV OF PTEROCLES. [Mar. 21, 



rhaptes lays four, which in general appearance and so-called structure 

 resemble those of certain Partridges. 



The Plovers lay the same number. The Pigeons, on the other 

 hand, invariably lay only two ; and this is so characteristic of the 

 whole group that Bonaparte named them Bipositores. Again, all 

 the true Gallinaceous birds produce a great and indefinite number 

 of eggs. Therefore in this respect the Sand-Grouse are more nearly 

 allied to the Plovers than either to Grouse or Pigeons. 



According to an observation made in the Zoological Gardens of 

 London in August 1865, the period of hatching seems to be a little 

 more than three weeks : two eggs were laid at the beginning of August; 

 and the young birds came out on the 29th of the same month. 



But one of the most valuable points, as regards the systematic 

 position of the Pterocletes, is the fact that the young when hatched 

 are thickly covered with hairy down, and that as soon as their plu- 

 mage lias dried they are able to leave the nest and seek their food. 

 This removes them far from the Pigeons, which are the most de- 

 cided psedotrophic or gymnogenous of all the birds we know. 



Now to sum up. "We have seen that there are many points in 

 which the Pterochdse have striking resemblances to the Colnmbidse ; 

 but there are also many points in which they approach the Rasores ; 

 and it is difficult, if not impossible, to made out which chaiacters 

 are the more important. 



Prof. Parker was the first to point out clearly that there is a rela- 

 tionship between Sand-Grouse and Plovers ; and Prof. Garrod, in his 

 classification of birds, groups the Columbse, including Pteroclidse, 

 and the Limicolse, including Charadriidse, together under his order 

 Charadriiformes. But the Columbidae undoubtedly are related to the 

 Rasores through such forms as the Cracidse {Peristeropodes, Huxley) 

 and the Tetraonidse ; and, in addition, they are linked together 

 by Pterocles and Syrrhaptes. These circumstances show that there 

 exists a close relationship between Rasores, Columbae, Pterocletes, 

 and Limicolse. Phylogenetic tables as a rule are faulty from being 

 highly hypothetical, and from the imagination being frequently 

 drawn upon in their compilation. However, they can be useful, even 

 if they only show where our knowledge is yet insufficient, or why 

 systems hitherto made do not agree with more recent ideas. There- 

 fore I venture to draw the outlines of a branch of the avian stock, not 

 led by preconceived ideas, but solely guided by the consideration of 

 facts we kuow, or at least we have a certain right to believe we know. 



1. Rasores, Columbse, and Limicolae are nearer related to one 

 another than to the rest of the birds. 



2. If the Columbee approach nearer to the Charadrii than to the 

 Rasores, we can express this idea by a stock which gives off two 

 main branches : — one for the Rasores ; and another one which again 

 soon divides into two — one Columbine, and one for the Plovers (see 

 fig. 8). 



3. As the Pigeons have closer affinities to the Fowls than the 

 latter have to the Plovers, the Pigeons must be represented by the 

 middle branch, that to the extreme left remaining for the Plovers. 



