478 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



Fig. 4. OpMothrix propmqua: 



a, tentacle scale. 



b, first ventral arm spine near the disk. 



c, first ventral arm spine transformed into a hook. 



d, second arm spine. 



e, third arm spine. 



f, fourth arm spine 



g, dorsal spine. 



5. OpMothrix spinosissima: % 



a, lateral arm spine. 



6, second arm spine. \ 



c, dorsal spine. 



d, first arm spine transformed into a hook. 



e, tentacle scale. 



6. Ophiothrix purpurea: 



a, spines of the dorsal surface of the disk, 

 o, second arm spine. 



c, first arm spine transformed into a hook. 



d, tentacle scale. 



7. Ophiothrix punato limbata: 



a, second and third arm spines. 



b, first arm spine transformed into a hook at several places. 



c, club spines of the dorsal surface of the disk. 



d, tentacle scale. 



8. Ophiothrix pusilla: 



a, tentacle scale. 



b, first ventral arm spine transformed into a hook. 



c, dorsal arm spine. 



d, second, third and fourth arm spines. 



Plate 102. 



Fig. 1. Ophiothrix striolata: 



a, spines of the dorsal surface of the disk, 

 o, tentacle scale. 



c, second arm spine. 



d, first arm spine transformed into a hook. 



2. Ophiothrix stelligera: 



a, club spines of the dorsal surface of the disk. 

 &, club spines of the dorsal surface of the disk. 



c and d, first ventral arm spine transformed into a hook with three 

 or four branches. 



e, ordinary spines of the dorsal surface of the disk. 



f, bifurcated spines. 



3. Ophiothrix ciiiaris: 



a, club spines of the dorsal surface of the disk. 



4. Ophiothrix trilineata: 



a, lateral arm spines, 

 o, second arm spine. 



c, tentacle scale. 



d, spines of the dorsal surface of the disk. 



e, first arm spine transformed into a hook. 



