KEPTILES. 127 



which this piece is prolonged into two horns, terminating in the muscles. For its body consists, as in 

 Chamseleonidse, of two differently shaped segments, passing one into another without interruption, and 

 placed one before the other. The anterior has nearly the form of a lozenge, and is in connection, 

 by its antero-lateral borders, with the hook-clavicles [eoracozL,], and is much broader but shorter 

 than the posterior. It commences small, but gradually increases towards its extremity, until it 

 is about three times the breadth that it was at first. In an example of Crocodilus acutus, four feet 

 seven inches in length, the largest I have dissected, the length of the anterior segment [p/ts-sternum] 

 of the greater piece of the Sternum amounted to two inches one line, the greatest breadth one inch 

 eleven lines, whilst the length of the posterior segment of this piece of the Sternum was two inches 

 eleven lines, and its greatest breadth ten lines. The horns of the Sternum [xiphisternals] appeared as 

 prolongations of this piece, and thus are not movably connected with this by fibrous tissue. The 

 horns spring from the Sternum, in close contiguity, but diverge widely, are of moderate length, but of 

 small breadth, become attenuated at their extremities, are flattened from above downwards, and form a 

 pair of moderately convex arches, whose concave edge is turned forward and outwards. Their relative 

 length varies somewhat in different species. Thus, the proportion of their length to that of the 

 greater segment of the Sternum is, in 



Feet. Inches. Lines. 



Crocodilus acutus ..470 long O65 : 1 



Alligator lucius . . 3 4 8 = 0'69 : 1 



Alligator palpebrosus . 1 1 9 = O69 : 1 



Crocodilus vulgaris . 2 9 6 = O78 : 1 



Alligator punctulatus . 1 , = 00- 1 : 1 



. 



The other or smaller division of the Sternum [inter-clavicle'] lies beneath the lozenge-shaped 

 plate of the anterior, usually extends to the extremity of this plate, and always projects to a moderate 

 extent beyond it. As in the Scaly Reptiles, it lies in a corresponding fissure or groove of the larger 

 piece, and is connected to it in a similar fashion. As regards its form, it appears as a long, small, 

 tabular plate, rounded at the extremities, but not possessing everywhere the same breadth and 

 thickness. It is broadest under the most anterior part of the lozenge-formed plate of the Sternum, 

 and from this point becomes smaller toward* the extremities, especially towards the posterior extremity ; 

 on, the other hand, it gains in this direction proportionately in thickness. There are no indications 

 whatever of lateral prolongations. The larger piece of the Sternum [true Sternum] is cartilaginous, 

 yet in spots in the interior of older specimens, differing considerably in different individuals, sometimes 

 extensive and sometimes of only limited extent, we may occasionally find irregular deposition of 

 calcareous salts, which, as in the larger sternal piece of Scaly Reptiles, appear to form heaps of small 

 granules. The other or smaller piece of the Sternum [inter-clavicle'] is always thoroughly ossified, 

 and contains bone-corpuscles in tolerably close proximity to one another, having many canaliculi, and 

 possessing a roundish or more or less elongated form. In very young Crocodiles, that have recently 

 escaped from the egg, this piece is already quite compact. But as they grow, a certain number of 

 medullary cavities of moderate size make their appearance. 



In a specimen of Crocodilis acutus somewhat more than four and a half feet long it presented 

 the appearance of a spongy mass surrounded or invested only by a few lamellae of compact tissue. 



With the major piece of the Sternum in the Loricata a larger number of ribs are connected 

 than is the case in Scaly Reptiles. Thus, in the Alligators, in the Crocodilus vu/yaris and in Crocodilus 

 acutus, it is in relation with seven ; in Crocodilus biporcatus with eight, and in Gavialts Schlegdii with 



