Fig. S.— Atlanta Peronii (after Gegenbaur). a, Pliarynx ; &, lauccal ganglion ; c, tentacle ; d, 

 eye ; e, cevebral ganglion ; /, aorta ceplialica ; £/, pleuro-visceral connective ; 7t, columellar muscle ; 

 f, fc, osphradium ; I, vagina ; 7E, ctenidiura ; n, anus ; o, uterus ; p, nephridium ; <i, aorta ceplialica ; 

 /•, auricle ; s, ventricle ; t, aorta visceralis ; u, digestive gland (liver) ; v, ovary ; w, stomach ; x, 

 pedal ganglion ; y, operculum ; z, nietapodium ; 1, sucker of the fin-like foot (rudimentary sole) ; 2, 

 foot ; 3, auditory organ ; 4, cesoiOmgus ; 5, snout ; 6, salivary gland. 



23 



Fig. 9.— Pterotrachea (Firola) coronata (after Leuckart). u, Pharynx; &, proboscidal snout ; 

 *., (.'ye; rf, cerebral ganglion; e, pedal ganglion; /, pedal artery; g, intestinal canal; h, pleuro- 

 visceral connective; i, pari etc- visceral ganglion; 7., osphradium ; 1, ventricle; m, auricle; a, 

 anus ; o, ctenidium ; //, metapodium ; g, appendage ; r, aorta cephalica ; s, nerve running to the 

 metapodium ; t, artery ; ii, foot ; v, common pedal artery ; w, cephalic artery ; x, auditory organ ; 

 1/, buccal ganglion. 



