"Four stages in the development of the trilobite Agnostus nudus. A, Youngest stage with no mesosomatic somites; B and C, stages with two mesosomatic somites between the prosomatic and telsonic carapaces; D, adult condition, still with only two free mesosomatic somites." — The Encyclopedia Britannica, 1910

Agnostus Nudus

"Four stages in the development of the trilobite Agnostus nudus. A, Youngest stage with no mesosomatic…