508 MESSBS. BEDDARD AND PAESOKS OX [June 6, 



studied chiefly the ambiens muscle, the carotids, the gall-bladdei", 

 and the couditiou of the oil-glaud ; with the help of the variatious 

 afforded by the structures he propounded a scheme of classification 

 of the group differing in many important particulars from the 

 classifications in use before : he did not discuss, in the paper to 

 \\hich we now refer, the relations of the Parrots to other groups of 

 birds ; in this respect we shall follow his example and confine 

 ourseh'es to an attempt to indicate affinities between different 

 members of the group in the light of the facts which \^'e record 

 here for the first time. We prefer, however, rather to lay stress 

 upon the new anatomical facts than to insist too much upon the 

 accuracy of the grouping of the birds to \\hich they appear to lead. 

 It is very remarkable that Garrod should in this particular case 

 have ignored the characters afforded by the syrinx, an organ which 

 he was very fond of studying and using as a help to decide vexed 

 questions of affinity : thanks chieflx' to his interest in this organ 

 we have been able to examine a very large series of syringes of 

 many of the principal genera, which he collected together during 

 his tenure of the Prosectorship of this Society : to these a few were 

 doubtless added by Forbes, and we have carefully preserved those 

 of such birds as happened to die duriug the course of the present 

 research ; so that on the whole we can claim to have seen a fair 

 number of illustrative genera ; the organ, too, in our opinion shows 

 useful, because easily definable, characters for systematic purposes. 

 We shall commence by giving some account of the syrinx in a 

 number of illustrative genera. 



§ Syrinx. 



The syrinx of the Psittaci seems to show two main varieties. 

 a. In the following species there is a syrinx of the type which 

 is illustrated hi Plate XL. figs. 4, 5 {Cacaiua cristata) : — 



Cacatua cristata. 



triton. 



phillpj^inarmn. 



Microijlossa aterrlina. 

 Calyptorhyncli us haiiksi. 

 Stringops hahroptilus. 



The syrinx is in these species remarkable for the fact that the 

 first semirings of the bronchi are weak and cartilaginous and 

 are usually separated from each other by considerable tracts of 

 membrane. Cacatua itself represents the most extreme type ; in 

 Cacaiua cristata, for example (see Plate XL. fig. 4), when the syrinx 

 is seen en a lateral view the membrane occupies a great deal of the 

 outer lateral region of the commencement of the bronchus. 



The figure to which we ha^e just referred exhibits the syrinx 

 with the intrinsic muscles cleaned away, but the point of attach- 

 ment of the muscle is indicated by the circle (a in the figure) ; it 

 vill be seen from an inj-pection of that figure that the semirings of 



