64 SHOULDER-GIRDLE AND BREAST-BONE. 



The supra-scapula (s. sc.) is a very regular oblong, save that the upper margin of the bony 

 scapula (sc.) ascends as it passes backwards ; below, it is wedged between the arrested prse- 

 coracoid and coracoid shafts. Only the root of the now very broad, spatulate pra3-coracoid (p. cr.) 

 is ossified, and the nerve-passage lies in the proximal part of the suture which separates it from the 

 coracoid; this latter bone is oblongo-lunate, and nearly reaches to the glenoid cavity (gl.). 

 The extensive epicoracoid region (e. cr.) is much broader than in the last stage, and the 

 Sternum (st.) shows the extension backwards of the posterior angles, the flappy condition 

 of the margins (lower coracoid lips), the concavity for the pericardium, the oblique fissure 

 separating the right margin from the rest of the Sternum, and which appears to be the pri- 

 mordial divisional line, and the evident xiphoid process. In Plate III, fig. 10, I have given 

 the upper view of the Sternum of an adult, magnified twelve diameters, showing a very short 

 xiphisternum, a very irregular condition of both upper and lower coracoid lips, and especially a 

 remarkable chink, which would, if carried on, separate the Sternum in precisely the same way as 

 it seems to be primarily divided in fig. 8. Fig. 11 is the under view of that of another adult, 

 magnified twelve diameters, and showing a longer xiphisternum, with a strong keel that separates 

 the recti abdominis ; a thick mass between the oblique bevelling for the pectorals ; the lower 

 coracoid lips ; and a deep oblique chink, which may indicate the primary separation between a 

 small right and a large left moiety. The Sternum of another adult (Plate III, fig. 12, st.), which 

 with the rest of the figure is magnified eight diameters, shows a still longer xiphoid process, and 

 still more produced posterior angles ; but the anterior chink is less demonstrable. In this last 

 stage the supra-scapula (s. sc.) is relatively less oblong than the last, having a much more convex 

 front margin, and being less deep. The scapula (sc.) is much broader, because of the periosteal 

 filling in of the acute angle between it and the pra> coracoid (p. cr.). Here the pra3-coracoid is 

 narrower in front, and the epicoracoid (e. cr.) is broader. The three bones have coalesced, and 

 the coracoid (cr.) has ossified most of the glenoid region. This figure shows to what an extent 

 the epicoracoids can overlap each other in this group, where they attain their most exorbitant 

 dimensions. 



Example 3. Triton cristatus, Laurenti. 



For comparison with the last instance I give the parts of the Shoulder in the Warty Newt 

 (Plate IV, figs. 12 15 ; figs. 12 and 13 magnified six, and figs. 14 and 15 nine diameters). The 

 supra-scapula (s. sc.) of this large old male has the form which is found in the half-grown 

 Lissotriton (Plate III, fig. 13), being very deep, and oblong in shape. The scapula (sc.) is very 

 low and wide, and is almost anchylosed to the other bones ; the deep rounded corner between it 

 and the prse-coracoid (p. cr.) is filled in by periosteal growths. Part of the suture between the 

 latter bone and the coracoid (cr.) is seen in front of the nerve- passage. The coracoid has reached 

 still further into the extensive epicoracoid region (e. cr.) than in Lissotriton ; and both this and 

 the free part of the pra-coracoid answer very exactly to the corresponding parts in the half-grown 

 Smooth Newt. Plate IV, fig. 12 well shows the liberal growth of the primordial skeletal 

 substance, so ready to be metamorphosed in the Vertebrata generally, and yet so proof against 

 metamorphosis over such large areas in these larva-like creatures. The Sternum (st.) of the 

 Warty Newt is much like that of the smooth kind ; but the anterior oblique fissure is on the 



