"Portions of sections through the disc of medusae. The upper one of Lizzia, the lower of Aurelia. el, endoderm lamelia, or vascular lamelia; m, muscular processes of the ectoderm cells in cross section; d, ectoderm; en, endoderm lining the enteric cavity; e, wandering endoderm cells of the gelatinous substances." — Encyclopedia Britannica, 1893

Medusae

"Portions of sections through the disc of medusae. The upper one of Lizzia, the lower of Aurelia. el,…