The hyoid apparatus has no skeletal connection with the rest of the skull.
2. The Appendicular Skeleton.
This includes the skeleton of the two pairs of limbs and their girdles.
The Pectoral Girdle.
The pectoral girdle has an anomalous position, being situated internal or ventral to the ribs. It consists of three bones, a dorsal bone, the scapula, an anterior ventral bone, the precoracoid, and a posterior ventral bone, the coracoid.
The scapula is a small somewhat rod-shaped bone forming about two-thirds of the glenoid cavity. At its proximal end it is closely united with the precoracoid, the two bones ossifying continuously. It tapers away distally, and is directed dorsalwards towards the carapace.
The precoracoid forms an angle of about 130° with the scapula, with which it is completely fused at its proximal end. Its distal end is somewhat expanded and flattened, and is terminated by a fibrocartilaginous epiprecoracoid which meets its fellow. It takes no part in the formation of the glenoid cavity.
The coracoid is a large flattened blade-shaped bone forming about one-third of the glenoid cavity. It does not meet its fellow in a ventral symphysis, and is terminated by a cartilaginous epicoracoid. The glenoid articulating surfaces of both scapula and coracoid are lined by a thick pad of cartilage.
The Anterior Limb.
This is divisible into three portions, the upper arm, fore-arm and manus.