REPTILES. 



extends from page 7 to 17 of that invaluable paper. My own terms are enclosed in brackets 

 and italics, and I shall give references to my own plates : 



RATHKE, ' Brustbeius der Saurier,' pp. 7 17. 



V. As in the atypic Scaly Reptiles, so also in the typical Reptiles, the Sternum is usually 

 composed of two pieces of unequal size [Sternum and inter-clavicle]. To this rule the Chamae- 

 leonidae, up to the present time, constitute the only exception, for in them the bony piece [inter- 

 clavicle] is absent which corresponds to the smaller sternal piece of other Scaly Reptiles. In propor- 

 tion to the size of the whole body, the two sternal pieces are considerable larger in the typical Scaly 

 Reptiles than in the atypical ; and their position is so far different that in the atypical species the 

 smaller or under piece of the Sternum [inter-clavicle] , to a moderate or even to a considerable extent, 

 extends in front beyond the greater piece, on which account the one may be called anterior and the 

 other posterior. 



VI. The lower piece \manubrial splint or inter-clavicle} of the Sternum exhibits very 

 different forms in different species of the Scaly Reptiles. In general, however, we may distinguish a 

 central stem and two lateral prolongations. The axis of the central stem corresponds to the middle 

 line of the body. The bone is elongated, more or less flattened above and below, and either gradually 

 fines off into a pointed process posteriorly or retains its breadth to the extremity, which is merely 

 rounded or blunt pointed. The stem of the anterior piece, therefore, if elongated, has some resem- 

 blance to an awl (Varani, Lacerta agilis, Lyriocephalus margaritaceus, Agama mutabilis, and Opiums 

 torquatus}, or to the blade of a double-edged dagger (Tejus Teguixin, Ameiva vulgaris, Iguana tuber- 

 culata, Polychrus marmoratus, Uromastix spinipes, Platydactylus guttatus} ; or to the blade of a short 

 sword (Anolis carolinensis, Seps chalcidica, Lacerta ocellata, Basiliscus mitratus, Cyclodus nigroluteus}. 

 It is extremely rare for it to have great breadth in proportion to its length, and the form of a table, 

 but this occurs in Moloch horridus and Phrynosoma Harlanii. In the former it is an elongated triangle, 

 the base of which is directed forwards, and is somewhat rounded. In the latter it is as long as it is 

 broad, retains the same breadth everywhere, and behind presents a deep rectangular excavation. 



The two lateral processes of the anterior sternal piece [inter-clavicle] either diverge from the 

 most anterior part of the stem or from a part situated somewhat more posterior, and in both cases 

 present variations in length and contour in different species of Scaly Reptiles. In those species in 

 which they proceed from the most anterior part of the central piece or stem they are short, broad, and 

 rounded at their extremities, as in Basiliscus mitratus ; moderately long, slightly arched, and directed 

 outwards and backwards, as in Iguana tuberculata ; and similarly curved and directed, though longer in 

 proportion to the stem, in Varanus niloticus, Varanus ornatus, Varanus bivittatus, Polychrus marmoratus, 

 Anolis carolinensis, Opiums torquatus, and Phrynosoma Harlanii. Amongst those in which the alse or 

 lateral pieces proceed from a portion of the stem situated further back, they are very small and only 

 wart-like, as in Ameiva vulgaris and Moloch horridus ; moderately long, remarkably broad in proportion 

 to their length, much flattened, and altogether resembling wings, in Tejus Teguixin, Lyriocephalus 

 margaritaceus, Agama mutabilis, Platydactylus guttatus ; moderately long and broad, or rather small, 

 resembling a bean, and directed outwards, in Lac. agilis, L. ocellata, Uromastix spinipes, Seps 

 chalcidica, and in Cyclodus nigroluteus. The anterior extremity of the stem, which forms a point in 

 the latter species, projects beyond the alse only very slightly in Uromastix spinipes and Lac. ocellata, 

 but considerably, on the other hand, in Lyriocephalus margaritaceus and Cyclodeus nigroluteus. The 

 stem of the anterior sternal piece [inter-clavicle"] reaches to a greater or less extent further backward 

 under the posterior sternal piece [true Sternum], and the extent to which this occurs is in proportion 



