LETTERS USED IN TEXT-FIGURES. 



b. Branchial vessels. 



Be. Nephridiopore. 



ho. Building organs. 



br. gl. Brown glands. 



cc. Dorsal body-wall. 



til. c. Ciliated membranous channel . 



cm. Circular muscle. 



d. Alimentary canal. 



dm. Dorsal longitudinal muscle. 



glv. Ventral gland. 



hyp. Hypoderm. 



int. Intestine. 



hi. Muscular and other tissues connected with hook-rows. 



rag. Anterior stomach. 



mg'. Posterior stomach. 



n.c. Nerve-cords. 



n.p. Posterior nephridia. 



nu. c. Neural canals. 



oc. Eye-spots. 



oes. QEsophagus. 



om. Oblique muscles. 



op. Opercular lobes. 



p. Palps. 



ph. Pharynx. 



pc. Cephalic plate. 



per. Peristomium. 



pr. Prostomium. 



pv. Ciliated funnel^ and;, in Fig. 139,, proventriculus. 



r. Ridge. 



8pm. or $ . Spermatozoa. 



th. Thoracic glands. 



ul. Uncinigerous lamellae. 



vm. Ventral longitudinal muscles. 



vv. Ventral blood-vessel. 



