Page:Illustrations of the comparative anatomy of the nervous system.djvu/19

 PLATE Il.

VENTRAL ASPECT OF THE CRAB.

(CANCER PAGURUS.)

THE nervous ring is seen sending branches forward to the parts about the mouth, and to be joined by those passing on each side of the oesophagus from the brain; other branches are seen passing to the muscles of the thorax, to the legs, and the muscles of the tail. The tail is formed of many pieces, somewhat resembling the backs of the rings of the lobster, and in each of them slips of muscle are inserted for drawing it towards the thorax; the nerve divides into many branches, which terminate in the muscles, but there is not any appearance of ganglia, as in the tail of the lobster, scorpion, &c.