EXPLANATION OF PLATES. 
Abbreviations. 
a. Anus. 
ac. Anterior band of cilia. 
af. Anterior lobe of foot. 
ag. Accessory glands of hermaphro- 
ditic duct. 
ag 1 . First accessory gland of her- 
maphroditic duct. 
ag 2. Second accessory gland of her- 
maphroditic duct. 
an. Ankistrophore. 
ao. Aorta. 
au. Auricle. 
hg. Buccal ganglion. 
fern. Buccal mass. 
bw. Body wall. 
cc. Cephalocone, 
ccl. Left dorsal cephalocone. 
ccV . Left ventral cephalocone. 
ccr. Right cephalocone. 
ce. Cerebral ganglion. 
ce 1, ce 2, ceS. Cerebral nerves. 
ceh. Cerebro-buccal commissure. 
cm. Connecting membrane. 
cr. Chromatin mass. 
cw. Ciliated wall of esophagus. 
d. Dermal gland. 
eel, ee2, ecS. Egg cells. 
ef 1, e}2. Egg follicles. 
jn. Nerve to foot. 
go. Gonad. 
gr. Granule. 
h. Hook. 
hd. Hermaphroditic duct. 
i. Intestine. 
I. Lips. 
Iv. Lateral nerve of left visceral 
ganglion. 
me. Middle band of cilia. 
mf. Muscle fibers. 
m^. Mouth of first accessory gland 
of hermaphroditic duct. 
m,v. Mouth of vagina. 
ne. Nucleolus. 
ne. Nephridium. 
ns. Nephrostome. 
nu. Nucleus. 
o. Osphradium. 
oe. Esophagus. 
og. Osphradial ganglion. 
on. "Optic" nerve with ganglion- 
ated root. 
opg. "Optic" ganglion. 
osn. Nerve to osphradium. 
ot. Otocyst. 
■p. Penis, 
pn. Parapodia. 
pc. Posterior ciliated ring. 
pd. Pedal ganglion. 
pdl, pd4, pd5, pd6. Pedal nerves. 
pe. Pericardium. 
pf. Posterior lobe of foot. 
pg. Penial gland. 
pg 1 . First penial gland. 
pg 2. Second penial gland. 
ph. Pharynx. 
phe. Pharyngeal cavity. 
pi. Pleural ganglion. 
pin. Nerve of pleural ganglion. 
pn. Nerve to parapodia. 
po. Penial opening. 
vs. Penial sheath. 
ra. Radula sack. 
rg. Ganglion of rhinophore. 
rn. Nerve of rhinophore. 
rs. Receptaculum seminis. 
s. Sperm, 
.sa. Salivary gland, 
.sc. Spermatocysts. 
s/. Sensorj^ nerve fibers. 
,ss. Sensory surface. 
.'it. Stomach. 
t. Anterior tentacle. 
