PLATE VI. 



Class ECHINODERMATA. 



THE STAR-FISH (Asterias). 



FIG. 1. DISSECTION FROM THE DORSAL ASPECT, x . 



m. madreporic tubercle : &., 6. rays of the bivium : t., t., t. rays of the 

 trivium : s. stomach : c. hepatic cseca : o. ovaries : a. ampullae. 



FIG. 2. TRANSVERSE SECTION OF AN ARM. x 1$. 



h. hepatic cseca : o. ovary : a. ampulla : p. pedicel or tube foot : 

 w. water-vessel : Z>. blood-vessel : n. nerve. 



FIG. 3. DIAGRAM OF THE WATER- VASCULAR SYSTEM. 



m. madreporic tubercle : s. stone canal : c. circular vessel : r. radial 

 vessel : p. polian vesicle : a. ampulla : t. tube foot. 



FIG. 4. NERVOUS SYSTEM, x 1. 



o. oesophagus: c. circum-ossophageal nerve ring: r. radial nerve 

 trunk. 



FIG. 5. PEDICELLARLE. x 10. 



