ZOOLOGY. 515 



(5) " lu the normal pigeons a gall-bladder is present ; no gall-bladder 

 in Go7ira." 



(6) " In normal pigeons 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 family quite distinct from the Columbidie and the rest of the 

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

 graphic characters of the Oolumbte are remarkably uniform throughout. 



The family PteroclicliTB has been generally approximated to the co- 

 lumbine series. Fterocles arenarius " shows an arrangement of the 

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

 the proximal and Ihe 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 pigeons as these are from the Gallinse." 



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 pigeons." And 

 "from the central forms of the Limicola?, nearly all the modifications of 

 style observable in the Cariuatae could be traced without difficulty." 

 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 Galls 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 froQi the central type." 



Sometimes curious resemblances appear; thus, "between the style 

 of the median cubital coverts in LeptoiHilus,^ one of the Storks, and 

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

 tect any difference 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 Oathartidte 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 herein 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 pterographical; 

 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. LondoUj 1880, pp. 184-203.) 



