348 ON THE GENUS PTILOPUS. 



"^ (6) It does not matter which organs or which parts of organs are 

 claimed in the interest of sexual selection, if only the result is the same. 



" (7) These structures cannot^ when generically very old, represent 

 sexual selection alone, perhaps not at all. They can have taken upon them 

 other functions, and, for instance, serve the excellently flying Bucerotidse 

 as pneumatic organs, facilitating the flight ; nay, they can even have altered 

 their function in a third way, as, for instance, certainly in Buceros scutatus. 



" (8) Although the spongiosa of the protuberances is not constructed in 

 an irregular manner, especially not in Buceros, it nevertheless could not, till 

 now, be reduced to the laws which Meyer and Wolff have shown to come 

 into action with the human spongiosa ; but this was quite possible for the 

 spongiosa of the bills. 



" If w^e search for the reason of all these protuberances, sexual selection 

 will, as already has been pointed out, in most cases have come into action. . . . 



" But these protuberances were not bound to be developed successively ; 

 they could also have appeared suddenly, as a pathological phenomenon, either 

 in one individual or (because some were under the same conditions) in 

 several. But if it be correct, which is often reported, that females of birds 

 hafe a predilection for certain misformed males, which are, after our ideas, 

 not even beautiful, such pathological occurrences could become important 

 factors in sexual selection, and easily be transferred as an inheritance in a 

 wild state. That they occur in a wild state, Ptilopus insoUtus proves/' 



PTILOPUS JOBIENSIS (Schlegel). 

 (Plate LXVIL) 



Ptilopus humeralis, Schlegel (from Jobi)^ Nederl. T. v. d. Dierk. iv. p. 25 (1873). 

 Ptilopus humeralis jobiensiSy Sclilegel, Mus. P.-B. Col. 1873^ p. 16. 

 [Ptilopus insolitus, Schlegel^ ibid. ?) . 

 Ptilopus jobiensis, Schlegel; Salvadori^ Ann. Mus. C. Gen. ix. p. 198 (1876-77). 



Before saying any thing about this bird^ it may be well to make a few 



