358 THE VOYAGE OF H.M.S. CHALLENGER. 



Fig. 12. Ileriiipholis cordi/era, Lym., \*. Young with a disk only 5 mm. in diameter, 



from alcove, showing the primary plates 

 ((/,(/'). No radial shields have yet appeared. 



„ 13. OpMonereis reticulata, Ltk., '^f. 



„ 14. „ „ \^. Outer face of an arm bone. 



,, 15. „ „ Y- Inner face of an arm bone. Observe the 



hollow process above the umbo (1). 



,, 16. Amphiura hcUis, Lym., ^^. 



„ 17. ,, ,, "x*. Outer face of an arm bone. 



,, 18. ,, ,, \*. Inner face of an arm bone. 



,, 19. Amphilepis ■norvegica, Ljn., \*. 



PLATE XLI. 



Fig. 1. Ophiopeza fallax, Pet., ij^. The interbrachial scaling is omitted. 



,,2. ,, ,, \'^. Outer face of an arm bone. 



,, 3. ,, ,, \'^. Inner face of an arm bone. 



,, 4. Ophiomitra valida, Lym., \*'. Bones of a mouth angle from above, with the 



first arm bone («>') ; also the genital plate 

 (o) and scale (») in position: and a radial shield 

 (/) turned somewhat from the arm. 



,, 5. ,, ,, \''. Outer face of an arm bone. 



,, 6. ,, ,, ij°- Inner face of an arm bone. 



,, 7. Ophioplax Ijnngmani, Lym., ^y^. 



,, 8. Ophiolebes scorteus, Lym., ^{^. 



,, 9. OpMocamax hystrix, Lym., f. 



,, 10. „ ,, ij^o. Outer face of an arm bone. 



,, 11. „ ,, 5^°. Inner face of an arm bone. 



,, 12. Opjliiacantha cuspjidata, L}an., J. 



,, 13. ,, „ f-. Outer face of an arm bone. 



,,14. ,, ,, -J. Inner face of an arm bone. 



PLATE XLII. 



Fig. 1. Ophiothainnus vicarius, Lym., -y'. The peculiar genital plate (o) placed on top 



of the arm. The walls of the ovarial bursse 

 ((5,i5), composed of lime scales. 



