Sentence Examples with the word Polygordius

There appears to be little either in the development or in the structure of the Haplodrili to warrant the view held by Hatschek and Fraipont that Polygordius and Protodrilus are exceedingly primitive forms, ancestral to the whole group of seta-bearing Annelids (Oligochaeta, Polychaeta, Hirudinea and Echiuroidea).

A, ap, c, c.o, c.t, d.v, e, ep, g Whatever may be the conclusion as to the position of Dinophilus and Histriodrilus, it seems only reasonable to suppose that Polygordius and Protodrilus, so far from representing a stage in the phylogeny of the Annelida before setae were developed, have lost the setae, which are already in a reduced state in Saccocirrus.

The development of Polygordius alone is well known, having been studied by Hatschek, Fraipont and others.