OPHIURANS OF THE PHILIPPINE AND ADJACENT WATERS. 477 



FIG. 2. Ophiothrix longipeda: 



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



5, tentacle scale. 



c, first ventral arm spine commencing to be transformed into a hook 



toward the base of the arm., 



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



e, second arm spine on the same level. 



f, third arm spine in the terminal part of the arm. 



g, lateral arm spines. 



h, a lateral arm spine toward the base of the arms. 



3. Ophiothrix lepida: 



a, first ventral arm spine transformed into a hook. 



6, tentacle scale. 



c, spines of the dorsal surface of the disk. 



d, second arm spine. 



4. Ophiothrix marenzelleri: 



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

 6, tentacle scale. 



c, first ventral arm spine transformed into a hook. 



d, second arm spine. 



j third and fourth arm spine. 



5. Ophiothrix melanosticta: 



a, lateral arm spine. 



b, spines of the dorsal surface of the disk. 



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



d, club spine of the dorsal surface of the disk. 



e, tentacle scale. 



f t first ventral arm spine transformed into a hook. -* 



ff, third arm spine* 



h, second arm spine magnified. 



6. Ophiothrix martensi: 



a, tentacle scale. 



Z>, arm spines. 



c, first arm spine transformed into a hook. 



PLATE 101. 



FIG. 1. Ophiothrix nereidina: 



a, first ventral arm spine transformed into a hook. 



b, tentacle scale. 



c, three successive arm spines. 

 2. Ophiothrix plana: 



a, first ventral arm spine transformed into a hook. 

 6, tentacle scale. 



c, dorsal arm spine. 



d, second and third arm spine. 

 3. Ophiothrix proteus: 



a, lateral arm spines. 

 6, second arm spine. 



c, tentacle scale. 



d, first arm spine transformed into a hook. 



e, spines of the dorsal surface of the disk. 



