anes 
a Messrs. Hancoc« and Embleton on the Anatomy of Eolis. 201 
through it the Eolidide, from the degradation which M. de Qua- 
trefages and others from imperfect observations had too hastily 
imputed to them. 
EXPLANATION OF PLATES V. anp VI. 
Puate V. 
Fig. 1. Nervous system of EZolis papillosa: aa, median supra-cesophageal 
or cerebral ganglia ; 0b b, lateral supra-cesophageal ditto ; ¢ ¢, buc- 
cal ditto; dd, gastro-cesophageal ditto; ee, olfactory ditto; 
f, anterior median commissure ; g, posterior median ditto, or com- 
missure of the buccal ganglia; 4h, commissure between median 
and lateral supra-cesophageal ganglia; 7, innermost or shortest 
cesophageal nervous collar; 7, slender or middle ditto; 4, outer- 
most or widest ditto. 
Nerves from supra-cesophageal ganglia: Nos. 1 and 2, small nerves to skin 
of head; 3, olfactory tractus or nerves; 4, nerve to the outer lip ; 
5, ditto to skin of head between dorsal tentacles; 6, 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 month; 10 and 11, ditto to skin at side 
of head; 12 and 13, ditto to skin down side of body below the 
rows of papille; 14 and 14, ditto to skin of side of head near the 
tentacles ; -16, opticnerves ; 17, auditory ditto; 18, nerves to the 
foot; 19, ditto to skin down side of body to papille (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 cesophagus and stomach; 5, large ditto 
passing into the buccal mass ; 6, small ditto to back part of buccal 
mass. 
Nerves from cesophageal collars: #, minute nerves from innermost collar, 
destination unknown; §, genital and probably cardiac nerves; 
y, nerves from outermost collar passing into buccal mass; 6, single 
nerve from middle collar, probably gastric ; e, large nerve coming 
out of buccal inass from a ganglionic swelling, and passing to be 
distributed to glands of papillee of skin; ¢, the ganglionic swelling 
situated in buccal mass, from which the large nerve « comes off ; 
n, branch of communication between the large nerve e and the 
outermost cesophageal collar. 
Fig. 2. Nervous system of E. Drummondi. The letters correspond to those 
in last fig. except one, 0, which marks a small ganglionic swelling 
in connexion with middle collar and genital nerve. 
Fig. 3. Eye of E. picta: a, outer capsule; 6, pigmentary cup; ¢, lens ; 
d, capsule of ditto. 
Fig. 4. Auditory capsule of Z. papillosa: a, outer capsule; 0, inner ditto; 
c, otolithes. 
Fig. 5. Auditory capsule of E. picta: references as in last fig. 
Fig. 6. Two otolithes from Z. papillosa highly magnified ({th object-glass), 
showing nucleus and nucleolus, ; 
Piate VI. 
Fig. 1. Nervous system of E. 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; 6, nerve coming from same, 
