A TAXONOMIC STUDY ON PYROSOMA — METCALF AND HOPKINS. 269 



ra.=enteron. 



/. c— follicle cell. 



£.=ganglion. 



gl.= neural gland. 



g. s.=posterior gonadial sinus. 



/j.=heart. 



ira<.=intestine. 



I. to. = ventral lateral muscular system. 



I. m / .= dorsal lateral muscular system. 



/. o.= luminous organ. 



I. o / .=cloacal luminous organ. 



m. = mouth. 



n.= nerve. 



n.l-^n.8— nerves. 



nc. =nucleus. 



n. r.= neural rudiment. 



o.=ovary. 



orf.=oviduct. 



oc.= esophagus. 



oc. o.=esophagal aperture. 



o/;.=operculum. 



oi>.=ovum. 



p. = pigment. 



p. a.=primary ascidiozooid. 



pbr. =peribranchial chamber. 



pc. =pericardium. 



pc / .=pericardial tube. 



pft.=pharynx. 



ph. b.= peripharyngeal band of cilia. 



ph. s.=peripharyngeal blood sinus. 



?'.'/•= pylorus. 



r. i\=reniform vesicle. 



s.=stolon. 



s'.=stolon process. 



s. s.= stolon blood sinus. 



s£.=stomach. 



stg.= stigma. 



t.= testis. 



t.f. =test fibre. 



<n.=tentacle. 



t. p. = test process. 



t. s.=blood sinus to tunic. 



v. a. s.=ventral anterior blood sinus. 



vc. s.= visceral sinus. 



v. (f.=vas deferens. 



v. I. s.=ventro-lateral blood sinus. 



v. s.=ventral blood sinus. 



//. = yolk. 



