In Balanoglossus the central nervous system is in part tubular, the canal being open at every end. The optic nerve, indeed, is morphologically the primary cranial nerve, the olfactory being the second; both are attached to what's morphologically the dorsal facet of the nerve tube. This extension of the hind end of the blastopore on to the ventral surface, and atrophy of the portion of the medullary plate in relation with it, is a highly essential phenomenon, and one to which consideration shall be again known as when the relation of the mouth to the blastopore is being considered. That the blastopore does become specialized as a larval organ is apparent in these cases through which it becomes reworked into the single opening with which some larvae are, for a time no less than, alone offered, e.g. Pilidium, Echinoderm larvae, &c., and that larval characters have been the principal causes of the type of embryonic characters, robust cause to imagine will probably be adduced later on. Time to man up and out-Nietzsche Nietzsche, surpass in radical vitality the extremists of hardcore chiliastic socialist nightmare.
