IX 



SKELETON 



319 



first costal plate, protected by a cartilaginous pad. Near the 

 glenoid cavity arises a long process (PC in Fig. 65), placed 

 transversely and approaching its fellow. The distal end is con- 

 nected with that of the coracoid by a fibre-cartilaginous band. The 

 homology of this scapular process is not quite clear. The band 

 just mentioned favours the idea that the process represents 

 the precoracoid, but its being an outgrowth from the scapula 

 suggests that it is merely the much enlarged acromion. It 

 certainly does not represent the clavicle, which forms part of 

 the plastron : and this is net in contact with the shoulder-girdle 

 at all. 



F IG . 64. Diagram of the skeleton of Testudo elep/iantopus, after removal of the left 

 half of the carapace. The plastron is roughly indicated by a section through the 

 middle line. Fe, Femur, foreshortened ; Fi, fibula ; H, humerus ; 11, ilium ; Is, 

 ischium ; P.P., pubis ; R, radius ; Scap, scapula ; Tb, tibia ; u, ulna ; 3, third 

 cervical vertebra ; 1, 3, 5, first, third, and fifth fingers ; XIII, thirteenth (fifth 

 thoracic) vertebra. 



The pelvis is strong. Ilium, pubis, and ischium meet at the 

 acetabulum. The dorsal end of the ilium is generally broad- 

 ened, and is attached to one or both sacral vertebrae, but it is 

 also in contact with the superimposed last costal plate. This 

 additional connexion often becomes predominant and the sacral 

 vertebrae are partly or completely relieved of the iliac support, 

 fusing in this case more or less with the costal plates. The 

 pubes have strong lateral processes, directed obliquely forwards 

 and downwards. The pubes and the ischia, which latter are 

 much smaller, form broad symphyses, and these are connected 

 with each other by a longitudinal cartilaginous band (Chelone, 

 Trionyx) ; or the connecting bridge is broad and quite ossified 

 (Testudo), forming in the latter case two roundish obturator- 

 foramina. Cartilage frequently remains at the anterior end of 



