508 MESSRS. BEDDARD AND PARSONS ON [JlUie 6, 



studied chiefly the ainbiens muscle, the carotids, the gall-bladder, 

 and the condition of the oil-gland ; with the help of the variations 

 afforded by the structures he propounded a scheme of classification 

 of the group diilering in many important particulars from the 

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

 which we now refer, the relations of the Parrots to other groups of 

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

 ourselves to an attempt to indicate affinities between different 

 members of the group in the light of the facts which we 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 \vhich 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 afliuity : thanks chieflv 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 during 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. 

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

 number of illustrative genei'a. 



§ 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 in Plate XL. figs. 4, 5 (Cacatua cristata) : — 



Cacatua cristata. 

 ■ — — triton. 



pTiiliijpinarum. 



Microglossa aterrima. 

 Cahjptorhyncli us hanlsi, 

 Stringops hahropiilus. 



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

 first semirings of the bronchi are ^^eak and cartilaginous and 

 are usually separated from each other by considerable tracts of 

 membrane. Cacatua itself represents the most extreme type ; in 

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

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

 outer latei'al region of the commencement of the bronchus. 



The figure to which we have just referi-ed exhibits the syrinx 

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

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

 will be seen from an inspection of that figure that the semirings of 



