362 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



EXPLANATION OF PLATES 



Eeference Letters 



A. buc.= Buccal artery. 



A. c. = Anterior aorta. 



A. cut.' = Cutaneous artery. 



A. col. = Columella artery. 



A. g.— Gastric artery. 



A. go.= Gonad vessels. 



A. pall. = Pallial artery. 



A. ped. = Pedal artery. 



A. pen. = Penis artery. 



A. vis. = Visceral artery. 



Af. ct.= Afferent branchial vessel. 



An. = Anus. 



Ao.= Aorta. 



Br. v. = Branchial vessels. 



bucc. = Buccal ganglia. 



c. = Cerebral ganglion. 



C. c. = Occlusor muscle. 



C. cav. = Blood spaces in oeso- 

 phagus. 



C. p. =Cerebro pedal connective. 



c. d. m. = Centro dorsal muscle. 



c. gr. = Granular cells of renal 

 lamella. 



Caec. = Oesophageal caecum. 



cae. w. = Connective tissue of caec. 

 wall. 



cart. = Cartilage. 



cer. com. = Cerebral commissure. 



Col. mus.— Columella muscle. 



Con. t.= Connect- tiss. gland of 

 Leiblein. 



Con. = Connective tissue. 



Cor. = Cornea. 



Ct. = Ctenidium. 



ct. ax. = Ctenidial axis. 



ct. con. = Connective tissue of gill 

 leaflet. 



ct. e.' = Epithelium of gill leaflet. 



ct. ep. = Ctenidial epithelium. 



ct. gi. = Connect, tissue of ctenidial 

 axis. 



ct. mus. = Ctenidial muscles. 



ct. n. = Ctenidial nerve. 



Dg. con. = Connective tissue of 



gland. 

 Dg.d. = Opening of post, digestive 



gland duct. 

 Dg.d.' = Opening of ant. dig. gland 



duct. 

 Dg. gl. = Digestive gland. 

 Dg. gr. = Granules of gland cells. 

 Dg. nuc. = Nucleus of gl. cell. 



Eff. ct. = Efferent branchial vessel. 



Foot = Foot. 



Foil. ep. ±= Follicular epithelium. 



Ge. ep. = Germinal epithelium. 

 Gl. c. = Gland cells. 

 Go. = Gonad. 



l.r.r. = Dorsal retractor muscles. 

 L.t.b. = Lateral odontophoral 



bands. 

 Lam. pr. = Lamellae of secondary 



system. 

 Lam. v. = Vein of renal lamella. 

 Lens = Lens. 

 Ling. con. = Connective tissue of 



odontophore. 

 Ln. g. = Gland of Leiblein. 



M. = Mouth. 



m.v.r.= Median ventral muscles. 

 mem. = Membranous wall of larva. 

 M u. gl. = Mucous gland. 

 Mus. circ. = Circular muscles. 

 M us. col. = Transverse sections of 

 mus. fibres. 



N. ax. = Nerve of ctenidial axis. 

 n.ot. = Otocyst nerve. 

 neph. gl. = Nephridial gland. 

 Nuc. = Nucleus. 



Nuc. Int. C. = Nuclei of instersti- 

 tial cells. 



D. m. s. = Dorsal trans, muscle 



sheet. 

 D. pr. m. — Dorsal protractor 



muscles. 

 jD<7." = Lobe of stomach. 

 Dg. c. " Dg. c. ' — Cells of digestive 



gland. 



0. cav. = Lumen of oesophagus. 

 oe. con. = Connective tissue with 



longitud. muscles. 

 oe. con. ' = Connective tissue. 

 oes. = Oesophagus. 

 0p. = Operculum. 

 Op. n. = Optic nerve. 



