OPHIURANS OF THE PHILIPPINE AND ADJACENT WATERS. 273 



other characters these two specimens agree well with 0. stelligera, 

 and there can be no question of referring them to 0. elegans. It may 

 be noticed, furthermore, that this latter species is very close to O. 

 stelligera, from which it is distinguished especially by the broad 

 band which runs all along the dorsal median line of the arms and 

 which continues over the dorsal surface of the disk to the neighbor- 

 hood of the center, and by the club spines of the dorsal surface of 

 the disk, which end in two or three unequal sp mules ; it is for this 

 reason that I have assigned to O. elegans the specimen from station 

 5179 which I have recorded above. 



The specimens of 0. stelligera which possess club spines only on 

 the dorsal surface of the disk might be confused with certain species 

 such as 0. miles Kcehler and 0. infinna Kcehler. I have already 

 described the principal characters which distinguish the former 

 from 0. stelligera ('05, p. 91) ; I may recall that the most impor- 

 tant consists in the presence of very fine small spines on the distal 

 border of the upper arm plates; furthermore the arm spines of O. 

 miles are shorter and less strongly denticulate, and the radial shields 

 are large and largely naked. In order to facilitate comparison I have 

 thought it well to include three photographs of a specimen of 0. 

 miles collected by the Siboga (pi. 52, figs. 8, 9, 10) . As for 0. infirma, 

 the dimensions of its tentacle scale will not permit of ever confusing 

 it with O. stelligera. 



There remains to be compared with O. stelligera, O. ciliaris 

 (Lamarck). I described its characters in detail in 1904 (Kcehler, 

 04a, p. 102) from a reexamination of the original specimens studied 

 by Miiller and Troschel which are in the Paris Museum. But it 

 seems to me worth while, after having studied more closely the 

 microscopical characters of the club spines of the dorsal surface of 

 the disk in 0. stelligera^ to compare them again with those of 0. 

 ciliaris. 



First of all I may state that the only authentic specimens of O. 

 dliaris which we have are the types preserved in the Paris Mu- 

 seum; they are three in number and in a deplorable state of pres- 

 ervation ; furthermore, they are of small size and the largest reaches 

 scarcely 6 mm. in diameter. I include (pi. 52, fig. 6) a photograph 

 of the dorsal surface of one of these; it bears, in addition to the 

 club spines, a few short and thick true spines with the surface 

 rugose and provided with short and irregular denticulations ; all 

 intermediates may be found between the typical club spines and the 

 longest true spines. Both surfaces of a second specimen are shown, 

 with a greater magnification (pi. 53, figs. 6, 7) ; the dorsal surface 

 of the disk bears only club spines. I show also (pi. 52, fig. 7) the 

 third specimen from the Paris Museum, which is of very small 

 55269 22 Bui. 100 18 



