226 ZOOLOGY, 
The ovaries or testes, as the sex of the clam may be, are 
bilaterally symmetrical, blended with the wall of the visce- 
ral or liver-mass, and are yellowish. The genital openings 
t 
ee 
Ne | 
Fig. 159.—Nervons system of the clam, natural size. @, cesophageal ganglion ; 8,. 
commissure ant«rior to the mouth ; c, pedal commissure ; @, pedal ganglia ; e, tpg 
splanchnic commissures ; f, parieto-splanchnic ganglia ; 9, branchial nerves; f, d, pal- 
lia] nerves ; i, aprons nerves; &, anal nerves ; m, nerves to the anterior adductor.— 
Drawn by ‘W: K. Brooks, 
are paired and lie near the base of the foot. Both eggs and 
semen arise from the epithelium of the sexual glands. The: 
eggs pass out into the body-cavity, or accumulate between the: 
