1.   It occurred to the scientists that the size of the hypoglossal canal might serve as an index of the vocal abilities of modern and early humans.

2.   The Duke researchers had argued that a larger hole, or hypoglossal canal, meant larger nerves and more complex tongue function.

3.   The diameter of its hypoglossal canal was almost identical to those found in several species of chimpanzees and gorillas.

4.   The Duke scientists directed their research at the hypoglossal canal in all primates.

5.   The hole is the hypoglossal canal through which nerve fibers from the brain pass to control muscles of the tongue.

6.   Their hypoglossal canals fell within the range of those of modern Homo sapiens.