Bd VI: 4) THE ECHINOIDEA. 1 1 1 



Fig. 17. Valve of small globiferous pedicellaria of Aiistrocidaris canaliculata, from the 

 inside. ''=, i. 

 !> 18. Abactinal radiole of Aiistrocidaris canaliciilata. ^'S/i. 



Plate XV. 



Fig. I. Part of ambulacrum of Arbacia crassispina. ^/i. 



» 2. Valve of triphyllous pedicellaria of Arbacia Dufresnii. ^'5/,. 



» 3. Part of ambulacrum of Arbacia Dufrtsnii. s/i. 



» 4. The point of an actinal spine of Arbacia crassispina. ''/i. 



» 5. Valve of ophicephalous pedicellaria of Arbacia crassispina. ''"/i. 



» 6. » » » » » » Dufresnii. 7°/i. 



» 7. » » » » » » crassispina. 7°/i- 



» 8. The point of an actinal spine of Arbacia Dufresnii. '^/i. 



» 9. Ocular plate of Arbacia Dufresnii. '■'/i. 



» 10. Stalk of ophicephalous pedicellaria of Arbacia Dufresnii. '^^/x. 



» II. Ocular plate of Arbacia crassispina. ''*/i. 



» 12. Ambulacral plates of Tetrapygus niger. '°/i. 



» 13. Valve of tridentate pedicellaria of Arbacia Dufresnii. '•°',i. 



» 14. >■ ' » ;' » » crassispina. '°/i. 



» 15. Ambulacral plates of Tetrapygus niger. '°/i. 



Plate XVI. 



Fig. I. Tridentate pedicellaria of Sterechinus Agassizii. i°!i. 



» 2. Valve of tridentate pedicellaria of Loxechinus albus, ^^ji. 



» 3. Globiferous pedicellaria, small (oim, of Ä''otec/tinus magel/amcus (comp. Fig. 19). 5°/i- 



» 4. Sphœridia of Loxechinus albus. '7°/i- 



» 5. Tridentate pedicellaria of Loxechinus albus, so ^ 



» 6. The point of a secondary spine of Notechinus magellanicus. ^°/i. 



» 7. » ' :> » » ' '■ Sterechinus Agassizii. ^°/i. 



» 8. Group of spicules from tubefoot :» » ? ^"s/i. 



» 9. Spicules from tubefoot of Notechinus magellanicus; a. fully developed, b. develop- 

 mental stage. ^^5/i- 



» 10. Abnormal, two-headed triphyllous pedicellaria of Notechinus magellanicus; the left 

 head slightly restored. '°/>- 



» II. Secondary spine of young Notechinus magellanicus. ^°U. 



» 12. Primary » » » ; 3 so/j. 



» 13. Outer part of secondary spine, with the point regenerated, of Sterechinus Agassi- 

 zii. S°/z. 



J 14. Valve of ophicephalous pedicellaria of Loxechi/ius albus. ^V'- 



» 15. Globiferous pedicellaria of Sterechinus Agassizii. "t'/i. 



» 16. Valve of triphyllous pedicellaria of Loxechinus albus, ''"/i. 



