454 



Prof. T. Jeffery Parker. 



[Apr. 17, 



III. " Observations on the Anatomy and Development of 

 Apteryx" By T. Jeffery Parker, B.Sc, F.R.S., Professor 

 of Biology in the University of Otago, Dunedin, New 

 Zealand. Received March 20, 1890. 



(Abstract.) 



The chief materials for the present investigation consist of a, 

 number of embryos of the three common species of Ajpte^yx, which 

 naturally group themselves into ten stages (A — K) ; an eleventh 

 stage (L) is furnished by a bird a few weeks old, a twelfth (M) by 

 the skeleton of an adolescent specimen, and a thirteenth (N) and 

 fourteenth (0) by odd bones of young birds ; the adult may be con- 

 sidered as constituting a fifteenth stage. 



The embryos were, for the most part, well preserved, but not 

 sufficiently well for the purposes of exact histological study. The 

 single embryo belonging to stage A corresponds in most respects to 

 a chick of the fourth day. 



The author returns his sincere thanks to the Council of the Royal 

 Society for the grant from which the expenses of the investigation 

 were defrayed, and also to those who have assisted him in various 

 ways. His paper is illustrated with seventeen plates, depicting 

 the external form and anatomy of the various stages, and a number 

 of new terms are proposed in the description of the skeleton. 



The following account is abstracted from the author's summary of 

 results : — 



External Characters. — In stage C, corresponding with a sixth- 

 day chick, there is a well-marked operculum growing backwards 

 from the hyoidean fold, and covering the third (? and fourth) 

 visceral cleft. A rudiment of this structure is seen in the preceding 

 stage. 



In stage A, the limbs have already attained their permanent 

 position, so that, if the backward shifting of the appendages so 

 noticeable in the chick occurs in Ajpteryx, it must take place at an 

 unusually early period. 



From the first appearance of the feather papillae there are well- 

 marked pterylse and apteria, most of which can be made out with 

 tolerable distinctness in the adult. 



The wing of the adult has a well-marked pre- and post-patagium,. 

 and amongst its feathers may be distinguished nine or ten cubitais, 

 two or three metacarpals, one mid-digital, and a row of tectrices 

 majores. The barbicels of the feathers are slightly curved. 



The fore-limb passes through a stage in which it is a tridactyle 

 p aw with suhequal digits, followed by one in which it is a typical 



