ZOOLOGY. 515 



(5) " In the normal pigeous a gall-bladder is present; no gall-bladder 

 in Goura.^^ 



(6) " In normal pigeous incubation lasts 16 days, but extends to 28 

 days in Goura.''^ 



In view of these characters there seems to be no doubt that Goura is the 

 type of a familj' quite distinct from the Columbidse and the rest of the 

 columbine birds. It is noteworthy that, excepting Goura, the ptero- 

 grapliic characters of the Oolumbfe are remarkal^ly uniform throughout. 



The family Pteroclida? has been generally approximated to the co- 

 lumbine series. Pterocles arenarius " shows an arrangement of the 

 wing-feathers somewhat like that of the pigeons, especially so far as 

 the proximal and the distal areas of the cubital region are concerned. 

 But the distal imbrication of all the feathers next the manual region is, 

 in the Pterocletes, carried to excess. In this respect the Pterocletes 

 stand as far removed from the pigeous as these are from the Gallinje." 



With regard to the shore or wading birds, it is remarked that " if we 

 start with the Plovers as the representatives of the order," the ptero- 

 graphical characters "nearly approach those of the pigeous." And 

 "from the central forms of the Limicolai, nearly all the modifications of 

 style observable in the Carinatse could be traced without difHculty." 

 Thus, "in one direction, and at no remote distance from the Plovers, 

 we come to the Rails;" in another "gradations equally gentle conduct 

 us to the Gulls and the Terns." Again, "along another line of modifica- 

 tion we arrive at the Cranes. The Storks again stand at no great dis- 

 tance." Further, " each of the forms here mentioned, in turn, leads to 

 others more distantly removed from the central type." 



Sometimes curious resemblances appear; thus, "between the style 

 of the median cubital coverts in Leptoptihis,''^ one of the Storks, and 

 that of the turkey buzzards, or cathartids, Mr. Goodchild "failed to de- 

 tect any difterence of importance in respect of the feature specially un- 

 der notice. " So far as the imbrication of the wing-coverts is concerned, 

 Leptoptilus and the Cathartidte might even stand in the same family." 



On the other hand, some forms which agree closely with others in 

 structure differ considerably in the cubital covering. One of these is 

 the common Osprey or Pandion and another is the Kite or Milvus. 



The conclusions of Mr. Goodchild are very temperate and judicious. 

 " In regard to any conclusions connected with taxonomy that may be 

 drawn from a study of the facts hei'ein referred to, there will probably 

 be much difference of opinion." But " there can be little doubt, also, 

 that up to a certain point there is a remarkable correlation of particu- 

 lar styles of imbrication of the cubital coverts with certain structural 

 characteristics — osteological, myological, visceral, and pterogra[)hical; 

 so that, within certain limits, the disposition of the cubital coverts may 

 be taken as a kind of index to the presence, or the absence, of deeper 

 seated characters whose importance in relation to taxonomy is gener- 

 ally recognized." (Proc. Zool. Soc. Loudon, 188G, pp. 184-203.) 



