BIRDS. 167 



aberrant form, the Cariama, stands far off from any known Bird, although its isomorphism with 

 the GraJlse is so great as to have misled some of the greatest ornithologists. 1 



I shall consider the Raptores as forming four sub-families, namely, the Accipitrinas, Striginas, 

 Vulturina3, 2 and Serpentariina3 : this last group contains two genera, namely, Secretarius and 

 Dicholoplius, each of which ought to stand at the head of a distinct Sub-family. I do not quite 

 despair of finding some relatives of the Cariama amongst the South American Birds ; they would, 

 however, have to be sought in the direction of the Cracinse, rather than near the Storks and Cranes. 



The Shoulder-girdle and Sternum of the half-fledged Sparrow Hawk (Nisus communis) are 

 shown in Plate XV, figs. 711, figs. 7 and 8 being of the natural size, fig. 10 magnified two, 

 fig. 9 seven, and fig. 11 ten diameters. The scapula (sc.) is ensiform, the supra-scapular end 

 (s. sc.) is still soft; and so, also, is the base; the acromion (m. sc.) is blunt. 



The coracoid (cr.) has its head and epicoracoid region still unossified ; this part (e. cr.) is 

 considerably produced backwards ; the meso-coracoid spur is moderately developed ; and from the 

 head of the bone there has been segmented a thick, similunar^ praa-coracoid (p. cr.). The 

 clavicle (cl.) is very broad and flat at its shoulder ; it is strongly curved backwards, and even 

 upwards ; this is intensified in the adult ; the inter-clavicle (i. cl.) is small even in the adult. 



All the Raptores, from Falco io Dichotophus,s\\ow the Pelecanine character of a large prae-coracoid 

 segment ; but only in one kind, namely, the Serpentarius, does the inter-clavicle articulate by a flat 

 joint with the angle of the sternal keel, as in the Pelecaninse. The prae-coracoid, however, does not 

 ossify by itself in the Raptores, but receives its osseous matter from the clavicle (see fig. 11). It first 

 undergoes vertical cleavage into an anterior and a posterior part, the former continuing some time 

 as hyaline cartilage (c.), and the latter becoming converted into fibro-cartilage (f. c.) ; this forms 

 the gristly pad which abuts against the flattened lower surface of the head of the coracoid. The 

 osseous matter (o.) of the clavicle (cl.) then creeps into the anterior lamina, obliterating it, just as 

 the meso-scapular cartilage was obliterated before hatching ; lastly, the bony matter affects much of 

 the fibre-cartilaginous pad itself; a synovial cavity meanwhile being formed between this prae-cora- 

 coidean shoulder of the furcular rarnus and the head of the coracoid : none of these chariges could 

 have been guessed at by observation of the adult bones. The Sternum of Nisus communis (figs. 7 and 

 8) may be taken as typical ; it is short-oblong and broadest behind ; it has a considerable keel (k.), 

 which is sharply differentiated from the pointed rostrum (r.) ; behind, it is notched or fenestrate 

 (both in the same individual, see fig. 8) into three xiphoid processes. The costal processes (c. p.) 

 are short ; the coracoid grooves (cr. g.) overlap ; the right passing below the left, as is normal in 

 Birds ; and there are seven condyles for sternal ribs, the last becoming aborted. The osseous 

 matter (fig. 7) has grown from the two " pleurostea" (pi. o.) up to the condyles, and the " lophos- 

 teon" (lo.) has lost its distinctness; there is some disposition to form a fifth pair of centres, but 

 they are not very distinct. Fig. 10 shows how the bony matter creeps into the body of the 

 Sternum; and fig. 9 shows that the "lophosteon" is an endosteal deposit originally, as in the 

 Reptiles the bony matter creeping in two tracts into the hyaline cartilage. In the Owls, the 



1 For instance, G. St. Hilaire, Burmeister, Martin, Reinhardt, and Nitzsch (see his ' Ptery- 

 lography,' translated by Dr. Sclater, Ray Soc., 1867, pp. 122, 123). In a recent conversation with 

 M. Alphonse Milne-Edwards I was very pleased to find that no place amongst the Gralla? had been 

 found by him for this bird. 



2 The Cathartinee deserve to be separated from the Vultures, and the Falcons from the Hawks 

 and Eagles. 



