IX 



SKKLKTON 



319 



first costal plate, protected liy a cartilaginous pad. Xear the 

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

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

 nected with that of the coracoid by a tibro-cartilagiuous band. The 

 homology of this scapular process is not ipiite clear. Tlie band 

 just mentioned favours the idea that the process represents 

 tlie precoracoid, but its being an outgrowth from the scapula 

 suggests that it is merely the much enlarged acromion. li 

 certainly does not represent the clavicle, which forms part of 

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

 at all. 



Fig. 64. — Diagi-am of the skeleton of Testudo elcphantopus, after removal of the left 

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

 middle line. Fc, Femur, foreshortened ; /'/, fibula ; 11, humerus ; II, ilium ; /.v, 

 ischium ; P.P., pubis ; R, radius ; Scap, scapula ; Th, tibia ; v, 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 

 vertel)rae 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. Tho ])ubes and tlte ischia, which latter are 

 much smaller, form l)road symphyses, and these are connected 

 with each other by a longitudinal cartilaginous band (Chelone, 

 Trionyc/-) ; or the connecting bridge is IVroad and (juite ossified 

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

 foramina. Cartilage frequently remains at the anterior end of 



