Skeletal bones orientated in the axial sense, comprising the neurocranium, branchial skeleton, vertebral column and intermuscular bones and ribs.
Glossary: axial skeleton
The upper angle between a fin and the body of a fish, most often used in reference to the pectoral fin.
Glossary: axillary process
A modified, often elongate, scale or group of scales located at the base of the pectoral or ventral fins in some fishes.
Used in reference to an unpaired anatomical structure, e.g., an azygos vein.