76 MR. FORBES ON THE STRUCTURE OF NASITERNA. [Feb. 17, 



highly specialized seluroid type. Very little else in the structure or 

 the palseontological history of the Dog indicates that it has passed 

 through a feline stage in its development ; and its more complex 

 brain may have been evolved quite independently from a primitive 

 form. A comparative study of the development of the convolutions 

 of the brain in the Dog and other Carnivora would throw light upon 

 this subject. 



2. On some Points in the Structure of Nasiterna bearing on 

 its Affinities. By W. A. Forbes, B.A., F.L.S., Scholar 

 of St. John's College, Cambridge, Prosector to the 

 Society. 



[Received February 12, 1880.] 



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 Cacatuince. 



Although two accounts have been published of some points in the 

 anatomy of Nasiterna piisio — first by Mr. Sclater when describing 

 that species ', and secondly by Signor Camerano, in a paper read 

 before the Turin Academy of Sciences", — nothing very definite has 

 resulted from them tending to elucidate this doubtful point. Mr. 

 Sclater was inclined to regard it (/. c. p. 622) as " an aberrant form 

 of the PsittacincB .... unless it can be allowed to stand as the type 

 of a distinct subfamily, which would probably be more correct." 



At my request, some fifteen months ago, M. Alphonse Milne- 

 Edwards was kind enough to forward to the late Prof. Garrod a spe- 

 cimen (in spirit) of a Nasiter?ia, probably N. pygmcea, for dissection ; 

 aud I now place before the Society a few statements on its structure 

 as recorded in his MS. notes. 



As in all other Parrots, except in certain species of Cacatua and 

 in Licmetis tenuirostris, there are two carotid arteries in Nasiterna 

 (a fact previously recorded by Camerano), both of which run in the 

 normal manner in the hypapophysial canal. As in all Parrots with 

 the carotids so disposed (except some individuals of Stringops), the 

 ambiens muscle is absent. The furcula is represented only by a 

 rudiment at the upper end; and the orbital ring is incomplete. As 

 the oil-gland is present, the formula for Nasiterna, adopting the 

 system used by Prof. Garrod in his paper on the anatomy of the 

 Parrots ^ will be 2 , — , — , -f- , as in Agapornis, Stringops, Geopsit- 

 tacus and their allies. 



Pterylographically, I have been able to ascertain that Nasiterna 

 pygmcea agrees generally in the form and disposition of the tracts 

 with such genera as Gyelopsitta, Psittinus, &c., and differs from the 

 Cacatuince in the absence of the crest and naked head-space {cf. 



I P. Z. S. 1865, p. 620. 2 Atti Eeale Acad. Torin. xiii. 1878, p. 301. 



3 P.Z.S. 1874, p. 69ii. 



