Science Art: Mouth of Petromyzon Marinus with its Horny Teeth,

From FM Balfour's WORKS, Vol 3: https://archive.org/details/theworks03balfuoft

This is a “more definitely suctorial mouth with horny cuticular teeth,” according to Francis Maitland Balfour, a British biologist with a particularly distinguished name and a delicate sense of prose, who was, until his untimely mountaineering death, viewed as the successor to Charles Darwin.

This lamprey’s face is from Volume 3 of his Works, which can be found on archive.org.