BIRDS. 169 



and at the narrowest part the ossification ceases suddenly ; there is then an elegant heart-shaped 

 leaf of hyaline cartilage, in which a unique ossicle appears the "urosteon" (u. o.) ; if this part 

 had been quite segmented off, we should have had a free " metasternum." All these are 

 characters belonging to the Cariama, and showing its generalised nature. As a rule the coracoid 

 grooves overlap in the Raptores ; they do not quite meet in Athene ; are still further apart in Strix 

 ftammea ; and are most widely separated in the Cariama, in Serpentarius, and in Falco peregrinus . 

 the skull of this latter bird, the very noblest of the entire Family, is the one which throws most light 

 upon that of the Cariama. The " rostrum" is moderately developed in all the diurnal kinds, but is 

 very small in the Owls, especially in Strix flammea ; in the Cariama (Plate XIV, tig. 11 r.) it is 

 less than in the Secretary Bird, and is intermediate between that of the Hooping-owl (fig. 14, 

 r.), and that of the Screech Owl (Strix Jlammea}. The costal condyles are five or six in number 

 in the Raptores generally, there are six in Elanus, Ulula, and Percnopterus ; Gyps fulvus has 

 four, and these are very large ; and the Cariama has four very large costal condyles for four 

 large sternal ribs, on each side ; in front of these there is a very small sternal rib, attached by 

 ligaments (fig. 11). As in Falco asalon and F. peregrinus, the Cariama has a free abdominal rib on 

 each side (fig. 11, a. r.) ; it may be seen on the left side in Ulula aluco. The sternal ribs of 

 the Secretary and the Cariama are equally stout ; the former has a sixth pair reaching the 

 Sternum. 



Sub-ordo " PIC ARLE." 1 



This provisional Group has the Woodpecker (Picus) for its centre, this being a medium 

 type ; the ultra type, or that which has the characters of this Sub-order in the highest degree, is 

 the Parrot (Psittacus) ; here this group culminates : the most aberrant forms are the Goat- 

 suckers (Caprinmglus), and Humming-birds (Trochilus). 



The families which I have studied most are the Psittacinse, Picinse, Ramphastinae, Muso- 

 phaginae, Cuculinse, Bucerinae, Alcedinae, Meropinse, Coraciinae, Galbulinse, Caprimulginse, 

 Cypselina?, and Trochilinae. 



Family" PSITTACIN^E." 



Examples. Psittacus erythacus, Linn. ; Agapornis pullaria, Linn. ; Striffops habroptilus, 

 G. R. Gray. 



The Shoulder-girdle of the Parrot-tribe is most perfect in the larger species ; the smaller 

 kinds often have the clavicles absent. This is shown in Plate XIV, fig. 1 5, which represents the 



1 I learnt this term from Dr. Sclater, but my use of it will be much wider than his ; I want it to 

 take in all those arboreal Birds which are neither Passerine on one hand, nor Gallinaceous (e. g. 

 the Pigeons) on the other. Many of Cuvier's Passeriuse must be arranged round Picus, viz. his 

 Tenuirostres, and part of his Fissirostres, and not in the neighbourhood of the true Passermse. 



22 



