XaiTrl, hair, g obs, foot), a zoological class, including the majority of the Annelida, and indeed, save for the Echiuroidea, co-extensive with that group as usually accepted.
Ray's "Insects" comprised the Arachnids, Crustacea, Myriapoda and Annelida, in addition to the Hexapods.
C. Maclntosh, A Monograph of British Annelida: I.
ANNELIDA, a name derived from J.
This Trochosphere is the characteristic larva of Mollusca, Annelida T OT (After Abbott, T5ky5 Zool.
That Polygordius, Protodrilus and Saccocirrus are on the whole primitive forms, and related to each other, there can be little doubt, but their place amongst the Annelida is difficult to determine.
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 course of development here outlined, in which the nauplius gradually passes into the adult form by the successive addition of somites and appendages in regular order, agrees so well with the process observed in the development of the typical Annelida that we must regard it as being the most primitive method.
The definition just quoted might include all animals belonging to the groups of the Arthropoda and Annelida, and U.