112 Mr. A. R. Wallace 07i the Genus Pitta. 



was not in this direction, biit through the intervention of the 

 Malay Peninsula. The position of the Anamba and Natuna 

 Islands, and a sea under fifty fathoms deep, show the probable 

 line of connexion of Borneo with Malacca, while the narrow and 

 island-choked strait west of Singapore indicates the point of junc- 

 tion with Sumatra. At this time Banca was already isolated ; 

 its rocky surface and mineral products show a great resemblance 

 to the peninsula, from which it was probably separated at a still 

 earlier period. There is therefore a, prima facie case for consider- 

 ing Banca to be an older island than Sumatra or Borneo, If so, 

 the fact of its possessing these peculiar species is exactly what 

 we might expect, instead of being the hopeless puzzle it seems 

 to be if we only take into consideration the present position of 

 the surrounding islands. I have dwelt somewhat fully on this 

 case, because it is one of the most interesting with which I am 

 acquainted ; and though the explanation I have offered of it is 

 in a great measure hypothetical, it shows in a most forcible man- 

 ner how impossible it is to understand the curious problems pre- 

 sented to us by the geographical distribution of animals, without 

 taking into consideration all the probable and possible changes 

 which may have recently taken place in the distribution of land 

 and water on the earth's surface. 



The position which the genus Pitta should hold in a natural 

 arrangement of birds, and its relations of affinity to the other 

 genera and families of Pcrchers, are problems which cannot yet 

 be said to be satisfactorily solved. By most recent authors Pitta 

 has been considered to belong to the same family as the Ameri- 

 can Ant -Thrushes, along with a host of other genera of obscure 

 affinities. Messrs. Horsfield and Moore include all these as a 

 subfamily of the true Thrushes, while Cabanis and Dr. Sclater 

 consider them to belong to distinct sections of Passeres. Bona- 

 parte, in his family Pittid^e, included several other genera, such 

 as Brackypteryx, Pnoqnjga, and Myiophonus, all inhabiting the 

 same countries as the Pittas, and having considerable resemblance 

 to them in form and habits, but differing totally in coloration. 

 Mr. Elliot, in his ' Monograph of the Pittidcs,' gives only the 

 species of Pitta, to which I presume he intends to restrict the 

 family. 



