iviessrs. HancocK and Embleton on the Anatomy o/Eolis. 201 



tlirough it the Eolididce, from the degradation which M. de Qua- 

 trefages and others from imperfect observations had too hastily 

 imputed to them. 



EXPLANATION OF PLATES V. and VL 

 Plate V. 



Fig. 1. Nervous system oi Eolis papillosa : a «, median supra- oesophageal 

 or cerebral ganglia ; h b, lateral supra-cesophageal ditto ; c c, buc- 

 cal ditto ; d d, gastro-oesopbageal ditto ; e e, olfactory ditto ; 

 f, anterior median commissure ; g, posterior median ditto, or com- 

 missure of the buccal ganglia; hit, commissure between median 

 and lateral supra-ossophageal ganglia; i, innermost or shortest 

 oesophageal nervous collar; j, slender or middle ditto ; k, outer- 

 most or widest ditto. 



Nerves from supra-oesopliageal ganglia : Nos. 1 and 2, small nerves to skin 

 of head ; 3, olfactory tracius or nerves ; 4, nerve to the outer lip ; 

 5, ditto to skin of head between dorsal tentacles ; G, ditto to oral 

 tentacles and roof of channel of mouth ; 7 and 8, ditto to skin of 

 side of head ; 9, ditto to muscles attaching buccal mass to skin, 

 and to sides of channel of mouth ; 10 and 11, ditto to skin at side 

 of head; 12 and 13, ditto to skin down side of body below the 

 rows of papillce; 14 and 1.5, ditto to skin of side of head near the 

 tentacles ; 16, optic nerves ; 17, auditory ditto ; 18, nerves to the 

 foot; 19, ditto to skin down side of body to pnpillae (respiratory 

 nerve) ; 20, ditto to skin of back ; 21, 22 and 23, ditto to skin of 

 back near median line. 



Nerves from infra-cesophageal ganglia: 1, small nerves to stomach; 2,3 

 and 4, smaller ditto to oesophagus and stomach ; 5, large ditto 

 passing into the buccal mass ; 6, small ditto to back part of buccal 

 mass. 



Nerves from oesophageal collars : a, minute nerves from innermost collar, 

 destination unknown ; ;3, genital and probably cardiac nerves ; 

 y, nerves from outermost collar passing into buccal mass ; 8, single 

 nerve from middle collar, probably gastric ; e, large nerve coming 

 out of buccal mass from a ganglionic swelling, and passing to be 

 distributed to glands of papillae of skin ; ^, the ganglionic swelling 

 situated in buccal mass, from which the large nerve e comes off; 

 jj, branch of communication between the large nerve e and the 

 outermost oesophageal collar. 



Fig. 2. Nervous system of E. Drummondi. The letters correspond to those 

 in last fig. except one, 6, which marks a small ganglionic swelling 

 in connexion with middle collar and genital nerve. 



Fig. 3. Eye of E. picta: a, outer capsule; b, pigmentary cup; c, lens ; 

 d, capsule of ditto. 



Fiff. 4. Auditory capsule of ^. papi//o5a : a, outer capsule ; 5, inner ditto ; 

 c, otolitlies. 



Fig. .!». Auditory capsule of E. picta : references as in last fig. 



Fig. 6. Two otolithes from E. papulosa highly magnified (|th object-glass), 

 showing nucleus and nucleolus. 



Plate VI. 



Fig. 1. Nervous system of £. coronata. Letters as in Plate V. figs. 1 & 2. 

 Fig. 2. a, buccal ganglion of E. papillosa slightly compressed and magnified 

 to show the vesicular contents ; b, nerve coming from same. 



