Bergh (for Lumbricus and Criodrilus), whose figures show a derivation of the entire nephridium from mesoblast, and an absence of any connexion between successive nephridia by any continuous band, epiblastic or mesoblastic. A midway position is taken up by Wilson, who asserts the mesoblastic formation of the funnel, but also asserts the presence of a continuous band of epiblast from which certainly the terminal vesicle of the nephridium, and doubtfully the glandular part of the tube is derived. [Please select]
0
Ectoblast: the outer wall of a cell; the ectoderm or epiblast. [Please select]
0
Epiblast: the outer germ layer of the embryo. [Please select]
Do you have a better example in your mind? Please submit your sentence!