32 EXPLANATION OF THE PLATES. 



PLATE II. 



Ophiacantha stellata, Figs. 16 — 18. Fig. 16, -',". under surface. The difference between 

 cond and third underarm-plates is to be noted. Just outside the second amall spine of 

 the second plate (on the arm to the right of the observer) may be seen protruding the minute 

 tentacle. Fig. 17, - 2 , n , upper surface, showing the small, deeply indented disk and the peculiar 

 side arm-plates, constricted between the joints, and rising suddenly into a ridge for the arm- 

 spiues. These characters, and the narrow, nearly covered radial shields, are those of the 

 typical 0. setosa, from which so many species now referred to the genus vary. Fig. 18, }, three 

 joints, seen from above, to show their characteristic form. 



Ophiacantha hirsuta, Figa 21 -23. Fig. 21, ','• under surface, with the unusually long 

 jaws, large mouth-tentacles, and the first, under arm-plate partly rolled ou itself. Fig. 22, ',', 

 upper Burface, showing the numerous fine spines. Fig. 23, ^, the lowest arm-spine, to exhibit 

 the peculiar thorns of its poiut and edges. 



Ophiomitra cervicornis, Figs. 19-20, ;. Fig. L9, under surface. The first under 

 arm-plate is folded on itself, and the small mouth-tentacle of the second pair protrudes between 

 it and the outer comer of the side mouth shield. <>n the under arm-plates, beyond, the tentacle- 

 scales have, first, the shape of thorny crescents, and then of little lobes. Fig. 20, upper surface. 

 showing the large radial shields and the coarse spines and stumps of the disk. 



Ophioplax Ljungmani, Figa 24, 25, ;. Fig. 24, upper surface ; the scales of the margin 

 are covered by a minute granulation. Fig. 25, under surface, showing the singular oval tentaele- 

 scale, with three or four minute ones on the under arm-plate. The tnterbrachial space is finely 

 granulate!. 



PLATE III. 



Amphiura anomala, Figa 26 28, ',". Fig. 26, under surface. On the righl side of the 

 mouth ai en three, and on the lef) only two mouth-papilla?, Above these are the large 



: and still higher may be seen the points of the scales of the tirst pan- of mouth- 

 tentacles. Fig. 27, upper surface. Fig. 28, arm-spines, from the side. 

 Amphiura Barbaras, Figs. 32 — 34, ', 7 . Fig. •"'-• under surface. The tentacles are thick; 

 it. I ij. :;:;. upper surface, with wide upper arm-plates. Fig. 34, arm-spines. 

 Amphiura flexuosa 35 37. Fig. 35, ',"• under surface, showing its verj 



minute, feeble scaling bride the mouth shield are two small mouth-papilla', followed by the 

 little jaws bearing the other pair of papilla?; beside these are seen the second pair of mouth- 

 tentacle 'ales Of the Bret pair. Fig. 36, Y. upper surface, with the radial shields 



I bj a central row of Scales, and some others, ill defined, on either side. Fig 

 third and fourth anil-spines, which differ from the n -st in being stonier, a little rough, and in 



,. at (he tip. See also Plate V, Fi 



Amphiura repens, Ki^v ..s 10, ',■■ Fig. 38, under surfs f the interbrachial 



naked, as in i bead like moutb-papUls 



:!'.', upper surface, which much resembles that of the Beat Indian A. la ' '<•'■ arm spinea 



Ophioceramis albida Amphipholis I ' I '-"■'. under surface 



The large - de i th shields, numerous mouth papUlu, sad ihorl genital openings are the char 



