270 BULLETIN OF THE 



Fig. 2. Tart of upper side 01 disk, showing the slender radial ribs, and the 

 first fork of the arm ; j. 



Fig. 3. The head of a radial rib and part of the interbrachial margin, enlarged 

 to show the granulation along the edge ; -}. 



Fig. 4. Astrophyton nudum. Tip of a twig, seen from below, showing the 

 continuous line of honks covered by a thick skin;- and, in front of them, two 

 short, conical tentacles ; -j -. 



Fig. 5. Three hooks, from the double alternating rows of the branches near 

 the base of the arm. From one, the skin has been stripped, showing the naked 

 hook ; A , a . 



Fig. 6. Ophioplocus Esmarki. Two joints near base of arm, seen from the 

 side ; 1 1 -. 



Fig. 7. Ophioncphthys plialcrctta. Two angles of the mouth, the base of the 

 arm, and a part of two interbrachial spaces ; \. 



Fig. 8. Portion of upper surface of disk, with base of an arm, and radial shields 

 surrounded by their peculiar wreath of scales ; ]. 



Fig. 9. An upper arm-plate, with a side arm-plate and its spines, showing the 

 peculiar thickened spine ; z ^. 



Fig. 10. Pedinura scptemspinosa (from the original at Leyden). Upper 

 arm-plates and spines, near disk, showing how the former are usually broken ; *. 



Fig. 11. An angle of the mouth enlarged, exhibiting the mouth-shield with its 

 small supplementary piece and the surrounding granulation. 



Fig. 12. Arm-spines, near disk, with the lowest one somewhat longest, and 

 having its base covered by a tentacle-scale ; j. 



Fig. 13. Two under arm-plates within the disk, with the pairs of pores between 

 them ; -}. 



Fig. 14. OpMomastix flaccidci. An angle of the disk and base of an arm. seen 

 from above, where are seen the peculiar upper spines thickened in different de- 

 grees; [ h 



Fig. 15. Two joints from below, showing two tentacles having no tentacle- 

 scales ; x- 



PLATE VII. 



Pcdinura infcrnalis. Mull, and Trosch. ; Ophiartlirum piditm~Lym.; Homolo- 

 gies of the skeleton of the arm and mouth-parts in Ojiltiotltrix, Ophiura, Opliio- 

 glypha, and Opliiomyxa. 



Fig. 1. Pcdinura infcrnalis. Part of upper surface of disk, to show the 

 characteristic arrangement of the naked plates ; ;. 



Fig. 2. Ophiarthrum pidnm. A corner of the disk and three upper Tin -plates, 

 with the patti rn lines and arm-stri] e ; {'. Specimen from Pelew Islands. 



Fig. 3. A tentacle and its scale; i {'. 



