(Chapter 22) Footnote 7:

A postclassical word in this sense, surcula, -ae f. occurs perhaps in Pliny Nat. 14.34 as the name of a vine (the form is uncertain, acc. to OLD); surculus, -i m. is a twig. Iugulum is the regular classical name for the clavicle. The 1555 edition omits both these Latin names.