Page:Illustrations of the comparative anatomy of the nervous system.djvu/13



PLATE I.

DORSAL ASPECT OF THE CRAB.

(CANCER. PAGURUS.)

The brain is seen giving off the nerves to the eyes and contiguous parts, and sending a long nerve on each side of the cesophagus, to supply filaments to the stomach and branchie, and pass backwards to join the nervous ring. The continuation of the nerves given off by the nervous ring to the legs is also exhibited. The nervous system in the fresh animal is very transparent, and cannot, without some difficulty, be distinguished from the muscles. It is very soft, and therefore requires a cautious dissection. Much advantage will be gained by the removal of portions of the shell from different parts, and as much as possible of the liver, ovaries, &e. ; it should then be immersed in water and gently agitated, so as to wash away the loosened particles, and afterwards placed in spirits of wine for a few days before any attempt is made to trace the nerves.