266 BULLETIN OF THE 



Fig. 8. Base of an adult arm-spine, showing the development and close solder- 

 ing of the side thorns to each other and to the central shaft; s y 1 . 



Fig. 9. Tip of an adult spine magnified, to show the central shaft and side 

 thorns beginning to form. 



Fig. 10. Hook from near tip of arm, corresponding to Fig. 4. At its base are 

 seen the holes of growth ; ^. For its position with its three arm-spines, see 

 PL VII., Fig. 16. 



Fig. 11. Ophiothrix rudis. A disk-stump; ^ 



Figs. 12, 13. Under and upper arm-spines from the eighth joint; the latter has 

 a blue belt round the middle ; - l p-. 



Fig. 14. Under arm-plate of the eighth joint; ^. 



Fig. 15. Ophiothrix stclligcra. Under arm-plates of the seventh, eighth, and 

 ninth joints, with one of the hooks ; -y-. 



Fig. 16. Upper arm-plate, near tin' disk; x p-. 



Fig. 17. Common form of disk-stump; -4"- 



Fig. IS. A similar one from above; x f a . 



Fig. 19. Rare form of disk-stump; H a . 



Fig. 20. Spine from the interbrachial spare below; x " 2 . 



Figs. 21, 23, 25. Ophiothrix pusilla. Unusual forms of disk-stumps; ^ Q . 



Fig. 22. The common form of stump on the back of the disk; L \-. 



Fig. 24. Stump from interbrachial space below; h p-. 



Fig. 26. Stump from interbrachial space near mouth ; —p-. 



Fig. 27. Side arm-plate of seventh joint with its eight spines and hook ; -j 1 . 



Fig. 28. Part of an under and a side arm-plate close' to tip of arm, showing the 

 one small arm-spine and the large hook; much magnified. 



Fig. 29. Upper arm-plates of sixth, seventh, and eighth joints, with two side 

 arm-plates, to show the triangular projection from the latter; \". 



Fig. 30. Upper arm-plates, near end of arm, with spines and side arm-plates, 

 showing the triangular projection from the latter. 



PLATE IV. 



Ophiothrix plana sp. nov. Ophiothrix Martcnsi sp. nov. Ophiopsammium Scm- 

 pcri gen. et sp. nov. Amphiura lozvis sp. nov. Ophiocnida (Ophiopihragmus 

 Ljn.) echinata (?) (longipeda Lym. MS.). Ophiothrix cxigua sp. nov. Ophiothrix 

 comata Mull. & Trosch. Ophiothrix ciliaris Mull. & Trosch. Ophiothrix 

 fumaria Mull. & Trosch. 



Fig. 1. Ophiothrix plana. Portion of upper surface of disk; nt the centre and 

 left the skin is partly dried to exhibit the underlying scales which on the right 

 are covered by the epidermis ; \. 



Figs. 2, 4. Different forms of the third arm-spine. Fig. 4 has its epidermis ; 

 s f 



Fig. 3. An upper arm-spine ; ^r. 



