OPHIURANS OF THE PHILIPPINE AND ADJACENT WATERS. 287 



arm spines in Ophiogymna elegans (pi. 103, fig. Id) and in O. ful- 

 gens (fig. 8e), O. pulchella (fig. 5a), and O. funesta (figs. 9a and e) 

 will show these resemblances. 



I may state that in all these species the tentacle scale is completely 

 lacking, or if it exists it remains only slightly developed and dis- 

 appears at a short distance from the disk, which is the case, as I 

 have just said, in O. fulgens and in O. pulchella. In the new species 

 the tentacle scale is also almost completely lacking. 



For all these reasons I believe that the two species which I had at 

 first assigned to the genus Ophiothrix — 0. fulgens and O. pulchella — 

 as well as the new species discovered by the Albatross, which is very 

 closely related to them, are better placed in the genus Ophiogymna 

 than in the genus Ophiothrix. I may add that still another species 

 which I have recently described and assigned to the genus Ophio- 

 thrix — O. convoluta from the Caribbean Sea — has, like the preceding 

 forms, which it quite resembles in its general appearance, flexible 

 and very contorted arms, and is without the tentacle scale ; although 

 I have not had occasion to study the articular facets of the arms, I 

 believe it necessary to assign it to the genus Ophiogymna. 



To sum up, I believe that it is necessary at present to refer to the 

 genus Ophiogymna the six following species : 



Ophiogymna elegans (Ljungman) (genotype). 

 Ophiogymna pellicula (Duncan). 

 Ophiogymna fulgens (Koehler). 

 Ophiogymna pulchella (Koehler). 

 Ophiogymna convoluta (Koehler). 

 Ophiogymna funesta, new species. 



In accordance with the preceding remarks, I propose to modify 

 and to complete the diagnosis of the genus Ophiogymna as follows : 



Ophiotrichidae with the arms very long and narrow, very flexible 

 and twining, capable of rolling up in every plane thanks to a struc- 

 ture of the articular facets of the vertebrae simpler than that found 

 in the genus Ophiothrix. The disk and even the arms may be cov- 

 ered by an integument which more or less completely conceals the 

 outlines of the subjacent plates; these plates themselves are only 

 slightly developed on the disk; they are lacking on the ventral sur- 

 face, and on the dorsal surface they are separated from each other b} 7 

 soft areas. The upper arm plates are present, but concealed under 

 the integument and more or less broken up; the cylindrical and 

 opaque arm spines show well developed denticulations only in their 

 terminal regions. The tentacle scale is absent, or if it occurs it is 

 reduced and disappears at a short distance from the disk. 



