186 SHOULDER-GIRDLE AND BREAST-BONE. 



These " coracostea" speak the same language as the anterior and posterior notches, and 

 tell of the essentially quinquefid nature of the Bird's Sternum ; and the innermost bar of the five is 

 primarily double or symmetrical, and retains in many instances marks of its early separate 

 condition. Some of the most interesting modifications of the Shoulder-girdle and Sternum of the 

 Gallinae are to be seen in the Pterocline and Columbine Families ; the latter is merely a 

 specialisation of the former, the Pigeon ascending amongst the " Altrices" from the Sandgrouse, 

 just as the Ibis and Stork ascend from the Pluvialine " Pracoces." Moreover, the Sternum of the 

 Sandgrouse and the Pigeon bridges over the space between that of the Gallinaceous Bird and the 

 Plover, by means of its small inner notch (' Trans. Zool. Soc./ 1864, PI. 41, fig. 4, x. s.). Compare 

 this with what is shown in the Partridge's Sternum (fig. 9). In the Sandgrouse the external xiphoid 

 fork is not more backwards in its direction than in the Pigeons. In the Columbinae (see Plate 

 XVI, figs. 20, 21, which show the sternal keel of a young Pigeon magnified eight and one hun- 

 dred diameters), the ossification of the Sternum is endosteal, as in Plovers and Birds generally ; 

 the ectosteal layer not appearing until some time after the endosteal deposit. 1 



Sub-ordo" TINAMIN^E." 



Example. Tinamus robustus, Scl. 



I must refer to what I have already written on the osteology of the Tinamous (op. cit., 

 Plates 39 and 41, fig. 1, pp. 225 229), but I think I may boast of having received clearer 

 light upon the subject since that time. 3 



Notwithstanding their perfectly Struthious skull and face, and their essentially 

 Struthious pelvis, the Tinamous, like the Fowls, are ornithically typical in their Shoulder- 

 girdle. The broad-ended scapula (op. cit., Plate 39, sc.) is quite segmented from the 

 coracoid, and is articulated with it at an acute angle : it has also a free acromion process, from 

 which a small meso-scapular segment has been cleft, the distinctness of which can be seen in the 

 adult, it having been ossified in some degree independently of the clavicle. A very small "prse-cora- 

 coid segment" has added substance, but not by independent deposit to the shoulder of the clavicle. 

 The furcula (op. cit., Plate 41, fig. 1, f. r.) is very small and U-shaped, and has no trace of an 

 inter-clavicle, such as is seen in Syrrhaptes (fig. 4, f. r.). The coracoid (cr.) is moderately long 

 and stout, and becomes broad in the epicoracoid region, both in front and behind. The head 



this has to do with the longer period of incubation. In the Talegalla, as Mr. Bartlett informs me, 

 the term of incubation is at least double that in the common Fowl ; and the chick, Minerva-like, 

 comes out fully accoutred, like a full-grown bird. 



1 For an excellent account of the Dodo's skeleton, with its free clavicles, and its common "meso- 

 intermediate xiphoids," I must refer the reader to Professor Owen's paper (' Zool. Trans.,' 1867, 

 pp. 49 85, pis. 15 24). In a Sternum belonging to S. Flower, Esq., of H. M. 13th Regiment. 

 I find a meso-xiphoid (primordial) notch, not figured in Professor Owen's paper (see pi. 18). In 

 that paper (pi. 15, fig. 2, and pi. 24, fig. 1) it is seen that the inner notch is lost in the adult 

 Didunculus ; these figures are from a specimen dissected by me and lent to the author. 



2 I have in my collection the skeletons of T. robustus, T. variegatus, and T. brasiliensis sive 

 major, all of my own preparing ; the subjects came to me, through Dr. Sclater's kindness, from the 

 Gardens of the Zoological Society. 



