A Contribution to our Knoiulcdge of the Anatomy of Cliamaeleons. 95 
Normally in all the groups which we have exarained three pairs of ribs 
are attached to the sternum. In exceptional cases four pairs may become 
attached (Text-fig. 8), or three on one side, four on the other (Text-fig. 9). 
The remaining ribs form continuous hoops behind the sternum. 
The simplest arrangement appears to be in Broohesia. The anterior 
part of the sternum in B. super ciliaris (Text-fig. 10) is well developed. 
The manubrium, which is comparatively short, is broad at the base and 
slender posteriorly. There is no xiphoid process. The first post-sternal 
hoop is placed a little way behind the sternal ribs. Siebenrock has also 
figured the sternum of Brookesia (Sitz. Akad. Wiss. Wien, 1893). 
C. ventralis (Text-fig. 11). — The manubrium is fairly long, is more 
clearly differentiated than in Broohesia, and possesses a slender xiphoid 
process which is underlain by the first or, in addition, the second pair of 
abdominal hoops. In C. damaranus much the same arrangement is to be 
seen, though abnormally four pairs of ribs on one side, three on the other, 
may articulate with the sternum (Text-fig. 9). In the figure the first 
hoop is in reality underlying the xiphoid process and is not intimately 
attached to it. 
In the Malagasy species of the genus Chamaeleon the sternal apparatus 
conforms more or less to that of the pmnilus section just considered, but a 
certain specialization has come about. The xiphoid process is better 
developed, and is variously shaped. Generally three if not four abdominal 
hoops underlie the xiphisternum, a strong membrane attaching the first 
hoop to the tip of the xiphoid process. The first three or four hoops are 
connected by muscles to the anterior part of the sternum. 
Text-fig. 12 shows the arrangement in G. hrevicornis, and a similar 
condition obtains in G. bifidus and in G. parsonii cristifer, though in the 
last a small bilobed cartilage articulating with the extremity of the xiphi- 
Text-Fig. 10. — Sternal Arrange- 
ment IN Brookesia. 
Text-Fig. 11. — Typical Arrange- 
ment OF Sternal Eibs in C. 
ventralis. 
