ON THE STRUCTURE OF NASITERNA. 131 



horn, continued for nearly the whole extent of the main part of the 

 horn, but considerably nearer its posterior than its anterior margin. In 

 its upper part are still observable minute blood-vessels, which have 

 become naturally injected. The horn has obviously been formed around 

 this dermal papilla, which, whilst the surrounding parts have become 

 hard and corneous, has remained soft and vascular for a while ; but 

 eventually its tissues have shrivelled up. It will be readily understood 

 how in this way the papilla has gradually been converted into a hollow 

 channel by the growth and elongation of the horn formed originally 

 round it. 



" In conclusion, I can only express my surprise that Prof. Cope has 

 apparently overlooked Judge Caton's excellent chapter on the Prong- 

 buck in his ' Antelope and Deer of America ' (1877). Judge Caton 

 himself has apparently witnessed the phenomenon several times ; and 

 his account of the growth of the horns (pp. 25-35) agrees very well with 

 my own observations, excepting as regards the point of origin of the 

 * prong/ If the shedding of the horns is * not periodical or even 

 frequent,' it is certainly strange that both his and the Society's speci- 

 mens should all have exhibited it. I may remark that the period of the 

 year assigned for shedding the horns by Mr. Caton also quite corre- 

 sponds with the dates of shedding here (November 7 and October 19)." 



[P.S. To-day (Dec. 2) the "prong" is still concealed beneath the 

 hairy covering of the pedicel, but is now very easily perceptible to the 

 touch. The hairy covering of the " pedicel " is thicker now than six 

 weeks ago, apparently owing to the growth of new hairs round it. 

 The horn above is still movable on the " pedicel." W. A. F.] 



23. ON SOME POINTS IN THE STRUCTURE OF 

 NASITERNA BEARING ON ITS AFFINITIES.* P.Z.S 1880, 



p. 76. 



FOR many years the true position in the series of Parrots of this very 

 singular little form, of which about seven species are now known, has 

 been a moot point amongst ornithologists, most authors placing it 

 amongst the Cacatuinse. 



Although two accounts have been published of some points in the 

 anatomy of Nasiterna pusio first by Mr. Sclater when describing that 

 species t, and secondly by Signor Camerano, in a paper read before the 



* Proc. Zool. Soe. 1880, pp. 76, 77. Read Feb. 17, 1880. 

 t P. Z. S. 1865, p. 620. 



K2 



