REPTILES. 105 



and forwards. As regards the position of the ends, they are found to terminate near the line of union 

 of the abdominal wall and the lateral surface of the body, or somewhat higher, and in the substance of 

 the latter. 



These parts of the skeleton are in proportion to the length of the plate of the posterior \true] 

 sternal bone, as well as in proportion to the length of the body, in some of the above-named Scaly 

 Reptiles of moderate, in others of great, length. In the following table are given my measurements 

 as obtained from specimens preserved in spirit of their length, as compared with the length of the 

 posterior sternal bone : 



In Zonurus cordylus = 0'93 1 



Phrynosoma Harlanii = l'X)0 



Istiurus amboinensis = T33 



Lophyrus giganteus = 1'35 



Basiliscus mitratus = 1 - 50 



Grammatophora barbata = 1'50 



,, Phrynocephalus caudivolvus = I 1 54 



Lyriocephalus margaritaceus = 1-55 



Agama colonorum = 1-55 



Uromastix spinipes = T66 



,, Moloch horridus = 1'77 



Draco viridis 1'87 



Stellio vulgaris = 2'25 



,, Agama mutabilis = 2 - 27 



1 

 1 

 1 

 1 

 1 

 1 

 1 

 1 

 1 

 1 

 1 

 1 

 1. 



XI. If the horns of the Sternal bone in typical examples of the Scaly Reptiles have united 

 [are connate] at their extremities with the ends of two ribs (see Plate IX), they are either connected 

 together by a thin layer of fibrous tissue or the osseous and cartilaginous tissues of the two bones 

 coalesce. The former condition occurs in Varanus ornatus, Varanus bivittatus, Tejus Teguixin, Lacerta 

 ocellata, Lacerta agilis, Plalydactylus guttatus, Platydactylus tegyptius, and Iguana tuberculata 

 (Plate IX, figs. 4 and 5) ; the latter (see Plate X, figs. 8 and 10) is present in Varanus niloticus, 

 Anolis carolinensis, Opiums torquatus, Agama umbra 1 , Cyclodus nigroluteus, Polychrus marmoratus, and 

 Seps chalcidica [see Plate X, fig. 2 ; but in my specimen of Cyclodus there is union of the two horns 

 to form a meso-sternal piece. W.K.P.] 



Amongst those Scaly Reptiles in which the latter of the two conditions obtains there are a few 

 in which there is scarcely any line of division between the horns of the Sternal bone and the ribs united 

 with their extremities. This is observed in Varanus niloticus, Seps chalcidica, and Anolis carolinensis 

 [and in Psammosaurus scincus and Monitor draccena ; see Plate X, figs. 8 and 10] ; but in others 

 there is a line at the point of union, and it is here also thinner than elsewhere. In others a similar 

 indented line is observable at a short distance from the Sternal plate, indicating the junction of the 

 sternal bone with the horn. 



The Sternal horns, thus united [connate, generally} at their extremities with two ribs, are in some 

 of the Scaly Reptiles rectilinear and parallel to one another Varanus ornatus and Varanus 

 bivittatus (see Plate X, fig. 10) ; or diverge moderately from one another Anolis carolinensis, Iguana 

 tuberculata (Plate IX, fig. 3), Calotes pictus, Polychrus marmoratus, and Seps chalcidica ; and with the 

 two ribs with which they are united form more or less convex arches. In others they, in the first 



1 It is remarkable that in Agama umbra the sternal horns are united at their ends to a pair of 

 ribs, although in other species of the genus Agama they terminate between the muscles. 

 14 



