64 ON THE GENUS PTILOPUS. 



this manner, and the females not : I mean, we have no satisfactory idea about 

 the mode and process of the alteration of colour and marking. 



" By the above diagram of geographical distribution, it is to be seen 

 that on New Guinea itself occur Ptilopiis rivolii and P. hellus ; but they 

 have not, till now, been found together — P. hellus only on the Arfak mountains, 

 P. rivolii on the coast of New Guinea, opposite Salawati. The Arfak 

 mountains can perhaps be considered equivalent to an insular elevation. On 

 the island of Mysore only P. speciosiis occurs, closely allied to P. hellus ; on 

 the island of Jobi only P. miquelii ; on the island of Mafoor P. speciosus and 

 P. rivolii together. This is obvious, Mafoor being a small island. But it would 

 be premature to reason about the facts, as perhaps a more accurate know- 

 ledge of the fauna of these parts of the globe than we now possess will show 

 us that the real geographical distribution of these four interesting species of 

 Pigeons is different from what we now suppose." 



The bird from which the Plate is taken is a good specimen, which was 

 kindly lent to me for the use of this work by Dr. Meyer, Director of the 

 Dresden Museum. It is represented the size of life. 



[To BE CONTINUED.] 



