THE GASTROPODS CHYTRA AND LIMNOTROCHUS. 
441 
EXPLANATION OF THE PLATES. 
Reference Letters. 
@., anus. 
&., aperture of the bile-duct. 
a.@., opening of the cesophagus into 
the stomach. 
ag., genital aperture. 
a.i., opening of intestine leading 
from the stomach. 
a7r., renal aperture. 
au., auricle. 
b.7., bueeal mass. 
¢@., spiral cecum. 
c.¢.pe.', left cerebro-pedal connective. 
¢.p., pericardial cavity. 
c.p.', left pleural connective. 
c.p.", right pleural connective. 
c.p.pe.', pleuro-pedal connective. 
Greve: 
g- gill. 
g.', gill-plume. 
g.c.', left cerebral ganglion. 
g.c."', right cerebral ganglion. 
g.e., cut edge of gill. 
g-G-, genital gland. 
g.g.', accessory genital gland. 
g-h., hypobranchial gland. 
g-p.', left pleural ganglion. 
g-p.'', vight pleural ganglion. 
g-pe., pedal ganglion. 
Fig. 1. Limnotrochus Thomson. 
2. y » 
3. ted 2»? 
4h 29 29 
D. s aA 
6. 19 ? 
ce ” ” 
8. 6 2 
9. ” 9 
10. Chytra Kirhkii. 
11. cS i 
The gill, with mantle reflected to the left. 
Female reproductive organs. 
g.8., salivary glands. 
g.si.. Sub-intestinal ganglion. 
g-Sp., Supra-intestinal ganglion. 
9-9-5 genital groove. 
2., Intestine. 
k., kidney. 
1., liver. 
nd., mantle. 
m.e., cut edge of mantle. 
n.p.', left pallial nerve. 
n.p.", right pallial nerve. 
?.St., Sub-intestinal nerve. 
2.Sp., Supra-intestinal nerve. 
| 2.v.', lett visceral nerve. 
| n.v.", right visceral nerve. 
| o., osphradium. 
@., esophagus. 
ot., otocyst. 
ov., oviduct. 
7., rectum. 
’ s., snout. 
s.c., crystalline style. 
S.S., Style-sac. 
st., stomach. 
é., tentacle. 
@, uterus. 
v., ventricle. 
2., Zygoneurous connection. 
Prats 38. 
Front view of shell. 
Back view of shell. Both natural size. 
Operculum, external face. x 6. 
Radula, 2 laterals, admedian and median 
teeth ; from a drawing by Mr. J. E. 8. 
Moore. Magnified. 
Nervous system, dorsal aspect. 
ud lateral aspect. Both x10. 
Otolith. Highly maguified. 
Female reproductive organs. X 7. 
Mantle-cavity, with mantle reflected to the 
myelin, SK Pe 
x 12. 
x 6. 
