This diagram shows the longitudinal section of the anterior end of the annelid. A, sagittal section; B, frontal section to show anterior portion of nervous system. b, brain; co., nervous collar about the mouth; c.v., contractile blood vessels; d, dissepiment; d.m., dermo-muscular wall; d.v., dorsal blood vessel; m, mouth; n.c., nerve cells; n.f., nerve fibers; np., nephridia; p, prostomium; ph., pharynx; s, setae; sn., segmental nerves; v.g, ventral chain of fanglia; v.v., ventral blood vessel. Only a portion of the blood vascular system is shown, and this appears unsectioned in the figure.

Annelid

This diagram shows the longitudinal section of the anterior end of the annelid. A, sagittal section;…