The following letters denote the same parts in all the Plates. 



I). Basal surface. 



br. c. Branching peripheral canal system. 



c. Costse. 



c. c. Cavity of peripheral canals. 

 c. g. - genital organ. 



ci/>. Comb (swimming plate). 



col. Colloblasts. 



c. tb. Cavity of tentacle-basis. 



cu. Cnpnle. 



c. z. Zone of cells, forming the cupule. 



e. Embryo. 



c. c. Brood cavity for the embryo. 



ret. Ectoderm. 



end. Endothelial lining of infundibulmn. 



cnt. Entodermal lining of genital or tentacular 



cavity; Entoderm. 



ep. Epidermis. 



c. s. Entodermal sac. 



excr. c. Excretory canal. 

 rxcr. o. opening. 



/ Transverse furrow; "snboral" cavity. 



g. Genital organ. 



gl. c. Gland cells. 



g. 2. Germinal zone. 



/. Ectodermal invagination. 



inf. Infundibulnm. 



/. /. Interstitial tissue. 



/. Lumen of the "chimney". 



in. Egg-membrane. 



in. f. Mesodermal tissue. 



o. Mouth-opening. 



or. Oesophagus. 



o. f. Opening from the "suboral" cavity into the 



lumen of the "chimney". 



07'. Ovary. 



of. Otolith. 



/./ Polar field. 



s. Apical sense organ. 



sec. f. Secondary tentacle. 



s. o. Secondary mouth opening. 



spz. Spermatozoa. 



st.f. Stomodseal (pharyngeal) folds. 



/. Tentacle. 



/. b. Tentacle-base. 



/. o. Opening of tentacle-sheath. 



/. r. Tentacle-root. 



fr. c. Transverse canal. 



f. s/i. Tentacle-sheath. 



fs. Testis. 



