510 MESSES. BEDDARD A>'D PAKSOKS Oy [June 6, 



little difPereuce ; here the first two rings of the bronchus are 

 equi-sized ; this at any rate applies to the two species Conurus 

 aureus and Conurus cruentatus, which are the only two that we have 

 examined Iroui this point of view. The genus Ara (species Ara 

 leari (fig. 6), Ara miliiaris) agrees with Conurus. Fsittacus (&g. 8) 

 is like these genera ; but Pionus (fig. 9) agrees more closely with 

 Chrijsotis. 



It will be obnous from what we have said and from the illus- 

 trations of the syrinx which accompany this paper that no hard- 

 and-fast line can really be drawn between the two groups into 

 w hich we divide the Parrots ; if it were thought desirable to draw 

 such a line it would be between the genus Cacatua on the one 

 hand and all the remaining Parrots on the other. Cacatua alone 

 has a syrinx in which the first bronchial semirings are incomplete 

 leaving a bare tract laterally which is easily Wsible when the syrinx 

 is viewed from the side: but in this genus there is another 

 peculiarity which we have not yet referred to — the intrinsic muscle 

 of the syrinx (fig. 5, rn) ends in a very narrow point which passes 

 into a fine tendon of attachment; in Chnisolis, Eos (fig. 2, m), &c., 

 the muscle is comparatively broad down to its actual attachment. 

 In this particular Microylossa and Stringops agree with Cacatua, 

 although they do not show the incomplete rings that have been 

 mentioned as characteristic of the latter genus. These genera in 

 fact are to this extent intermediate between Cacatua and the more 

 normal (at any rate more usual) form of sj^rinx in the Parrots ; 

 the rings are still, however, soft and cartilaginous, thus different 

 from Conurus, which is a further step in the direction of Chrysotis; 

 Chri/sotis seems to represent the opposite extreme to Cacatua. 

 Ara is a genus which is also intermediate in the characters of 

 its syrinx, it has ueakish and straight rings, as in Strinfjops for 

 instance ; but the muscles are as in the second group of Parrots, 

 and the general aspect of the syrinx is more in accord with this 

 placing of it. 



§ Myoloijy. 



We find that the Parrots are very much alike in their myology; 

 there are, however, a few points in which they show differences 

 and which may be useful for the purposes of classification. In the 

 first place, the arrangement of the tendons of the tensor patagii 

 varies considerably. Speaking generally (see Fiirbringer, Morph. 

 v. Syst. d. Yogel, Taf. xxii. figs. 4, 5, 6 : Sittace, Psittacus, Cacatua) 

 this muscle ends in a broad aponeurosis which lies between the 

 two layers of skin of the patagium, and in this aponeurosis are 

 three thickened bands which run down to the forearm to join the 

 tendon of the extensor longus at right angles ; from the lower 

 margin of this transverse tendon another slip runs down to the 

 ulna, having the same course as the patagial tendons, but not being 

 necessarily in the same line with any of them. The anterior 

 patagial tendon usually curves forwards near its lower attachment 

 and the posterior slightly backwards ; in addition to this the 



