AMPHIBIANS. 67 



ordinary Osseous Fishes on the other: like the Ray and Shark, however, as far as the 

 Shoulder-girdle is concerned, they have borrowed no parosteal growth from the skin and its 

 infoldings. 



The order in which my instances are described does not assume to be " systematic," in a 

 zoological sense. It will, however, harmonize unconsciously to a great extent with what is 

 really natural. The fifth Plate, which shows the development of the Shoulder and Sternum in 

 the common Toad and Frog, from my own dissection, may be passed over until the adult, or, as 

 in some cases, the half-adult forms (shown in Plates VI and VII) have been described. 1 



A. With no " Omo-sternum." 

 A 1. With no cleaving of the Shoulder-plate. 

 Example. Microps osoyrhyncftus, Fitzinger. 



Plate VII, fig. 11, shows the Shoulder-girdle of a young female of this minute Brazilian 

 Frog, seen in an antero-inferior aspect, and magnified four diameters. 



In this lowest Anouran the Shoulder-girdle, but for its three pairs of bony sheaths, would 

 answer very accurately to that of a young Shark {e.g. Galeus), before coalescence of the two 

 halves below. In this, as in all the Anourans (and as we shall see in all the Reptiles), there is 

 no real transverse fission of the cartilaginous bars, although the flexion of the " supra-scapula " 

 on the scapula (s.sc., sc.) is very considerable ; for the bony deposit stops suddenly, and the 

 intervening cells of cartilage become very, much flattened : yet no connective fibre is intruded. 

 The supra-scapula of Microps (Plate VII, fig. 11, s. sc.) is like the blade, and the scapula (sc.) 

 the handle of a pruning-knife ; the convex edge of the supra-scapula is only partially ossified by 

 endostosis, and the outer bony plate covers about three fourths of the surface. A narrow syn- 

 chondrosis bounds the scapula, both above and below, and the lower of these is continuous with 

 the cartilage of the glenoid cavity (gl). Like the scapula, the coracoid (cr.) is a phalangoid 

 ray, somewhat crescentically curved, and bounded below a narrow lunate band of soft cartilage. 

 Save that the supra-scapula has in this case its own shaft-bone, this little Anouran has pre- 

 cisely such a simple Shoulder-girdle as the Dinornis, 2 Emu, Rhea, Cassowary, and Apteryx 

 have. I have put in outline a supposed Sternum (st.) which, although not present in the 

 preparation figured, yet undoubtedly existed in the fresh state. 



A 2. With an arrested cleft in the base of the scapula, but with the coracoid simple. 



1 



Example. Hyl&dactylus celebensis, Schlegel. 



Plate VI, fig. 9 shows the Shoulder-girdle of a young male of this species, as seen from 

 above, and magnified three diameters. The specimen was from Ceylon. 



In this Frog we have the supra-scapula (s. sc.) normally large, spatulate in form, two fifths of 



1 All these, except Bufo, have been studied from Hyrtl's preparations. 



2 See Owen on Dinornis (part ix), ' Zool. Trans.,' 1866, vol. v, part 5, p. 356, plate Iv, figs. 2, 3, 4. 



