| OCR Text |
Show 76 MR. FORBES ON THE STRUCTURE OF NASITERNA. [Feb. 1/, highly specialized aeluroid type. Very little else in the structure the palaeontological 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. O n some Points in the Structure of Nasiterna bearing on its Affinities. By W . A. F O R B E S , 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 pusio-first by Mr. Sclater when describing that species', and secondly by Signor Camerano, in a paper read before the Turin Academy of Sciences2,-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 Psiltacince .... unless it can be allowed to stand as the tvpe 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 specimen (in spirit) of a Nasiterna, probably N. pygmcea, for dissection ; and I now place before the Society a few statements on its structure as recorded in his M S . 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 Parrots3, will be 2, - , - , + , 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 Cyclopsitta, Psittinus, &c, and differs from the Cacatuince in the absence of the crest and naked head-space (cf. 1 P. Z. S. 1865, p. 620. 2 Atti Reale Acad. Torin. xiii. 1878, p. 301 3 P. Z. S. 1874, p. 595. |
