Note on the Spinal Accessory Nerve of Long-necked Ungulates.



In a llama the spinal portion of the accessory nerve was grossly absent. The sterno-cephalic muscle was innervated by the second cervical nerve and, presumably, also by a branch from the bulbar portion of the accessory nerve.

Consideration of the literature indicates that the gross morphology of the accessory nerve and its relation to the sterno-cephalic and brachio-cephalic muscles are extremely variable features in the longest-necked ungulates (giraffe, camel, llama).