LIST OK RKKKIiENCIC-LETTERS. 



/. />. proboscis-pore. 



/;•. /. priniary lamella of cocnoccium. 



prol), st. proboscis-stalk. 



pst. peristome. 



pt. pcritoiicuin. 



p. V. postcrior vessel of stalk. 



p. V.' its termination on the alimontar)- caiial. 



;-. rectum. 



J\. I — 6. right arms. 



R. a. right arm. 



rcc. recess into wliich oviduct opens. 



s. '/a septum between proboscis and collar. 



s. -/^ septum between collar and metasome. 



sec. l. secondary lamella of coenoecium. 



s. o. sense-organ of embryo. 



sp. mass of spermatozoa. 



st. stalk. 



stom. stomach. 



stom.'- second stomach. 



/. testis. 



tent. tentacles. 



/. /. left testis. 



/. r. right testis. 



/. 7'. vessel of testis. 



it. l. upper lip. 



vac. vacuolated ectoderm of embryo. 



V. inv. ventral invagination of embryo. 



V. m. vitelline membrane. 



V. vies.''' ventral mesentery of collar. 



V. mes.^ ventral mesentery of metasome. 



V. i. ventral thickening of embryo. 



X. problematical tissue of collar-canal. 



j'. thickening of ectoderm near anus. 



yk. yolk. 



yk. a. its anterior subdivision. 



z. zooid. 



