FIG. 1 in A new look at the Cretaceous Lamprey Mesomyzon Chang, Zhang & Miao, 2006 from the Jehol Biota

FIG. 1. — Generalized anatomy of living lampreys: A, schematic sagittal section through head and pharyngeal region; the vessels, esophagus, respiratory tube, and parts of the heart are shown with portions cut away, rather than in sagittal section; redrawn after De Iuliis & Pulerà 2011, with the structures of the nasohypophysial complex labelled after Janvier 1974; B, the cranial skeleton of an adult lamprey, redrawn after Hardisty & Potter 1981; C, arrangement pattern of the cranial nerves, redrawn after Marinelli & Strenger 1954; D, oral disc of an adult lamprey showing the keratinous teeth and other associated structures. The dotted lines delineate the various fields. Redrawn after Renaud 2011.