REPTILES. 119 



continuous ends of two pairs of ribs are the counterparts of what is seen in the Iguana ; but in 

 that Reptile they are only partially segmented from the main part of the Sternum; they also 

 answer to the two additional meso-sternal segments of the Cyclodonts. No Oviparous 

 Vertebrate that I am acquainted with has perfect transve. . segmentation of the Sternum, not 

 even amongst the Birds ; but in that Class there are some Families with connate sternal ribs 

 (see Plate XI, figs. 12 and 13 which show this structure, in the Talegdla) ; it is also seen in the 

 Cracina?, Gallinae proper, and in the Anserine Palamcdea. Therefore, notwithstanding the 

 primordial homology of these parts with the " xiphisternal horns " of the Iguana, and with the 

 additional meso-sternal regions of the Cyclodonts, I really consider that they have, in this case, 

 determined themselves to be merely the uncleft extremities of the fourth and fifth ribs. 1 



Example 8. Stellio cordylinus, Gray. 



Plate XI, figs. 1 and 2, show the Shoulder-girdle and Sternum of this Lizard magnified two 

 and two-thirds in diameter. This very valuable instance of Lacertian structure has in its Shoulder- 

 girdle that which will repay careful study ; but its Sternum is that which makes it of most import- 

 ance. The supra-scapula (fig. 1, s. sc.) is a broad, high, curved, cartilaginous crest, having a five- 

 spurred cockscomb-like bony deposit in it ; its unossified upper part overtops its body almost 

 equally both ways, and it is very broad down to the scapula. This latter part (sc.) is wholly 

 ossified, as in Psammosaurus and Lcemanctus ; but it especially agrees with the latter in having 

 a flat meso-scapular (acromial) lobe in front (see Plate XI, fig. 1, and Plate IX, fig. 7, m. sc.) ; 

 and, as in that species, there is no prse-scapula ; the whole scapula is broad and flat. 



The coracoid (Plate XI, figs. 1 and 2, cr.) has the same complexity as that of Leemanctus 

 and of the Cyclodonts ; and, as in them, the prse-coracoid (p. cr.) is quite free, being separated 

 from the meso-scapula by the coraco-scapular notch (fig. l,c. s. n.), which is a large semi-elliptical 

 space. The meso-coracoid is not at all separated from the coracoid (cr.) but the head of the 

 coracoid runs a long distance into the prse-coracoid. 



The coracoid is a very broad ray, elegantly semilunar below ; and the epicoracoid (e. cr.) is 

 a well-shaped half-moon, with only the rounded anterior angle, where the prae-coracoid com- 

 mences, quite soft, or free from ossific deposit ; this is the part which is cloven from the rest to 

 form the " omosternal moiety " in the Tadpole. The oblique suture between the scapula and 

 coracoid, and the usual foramen in the head of the coracoid, are clearly seen; also the thick- 

 edged, cartilaginous glenoid cavity. Fig. 2 shows that the epi-coracoids in this flat-bellied Lizard 

 are kept far apart by the intrusion of the broad Sternum, a condition which is normal in Birds, 

 where the coracoids overlap only exceptionally. 



The clavicles (figs. 1 and 2, cl.) are very strong ; they also meet together, not as in the 

 Iguana (Plate IX, fig. 2), in front of the azygous bone, but below its anterior part; it is seen in 

 fig. 2 how that the inter-clavicle is clasped and embraced by the clavicles. These stout clavicles 

 are bluntly pointed above (fig. 1 , cl.), where they touch the front of the base of the overhanging 



1 I propound this the more boldly that I may weaken the influence of the merely regional terms 

 upon my own mind and that of others ; for whilst there can be no description without the use of 

 certain terms, yet, as these terms are often arbitrary, they are apt to clog the mental faculties, and 

 hinder when they ought to help. 



