OPHIURANS OF THE PHILIPPINE AND ADJACENT WATERS. 321 



Geneva, I have been able to examine the type of O. doderleini^ and 

 I include three photographs of it (pi. 72, figs. 1, 2, 3), which will 

 supplement the data given by Loriol ('99, p. 110, pi. -3, fig. 2) and 

 which will permit forming an opinion of its affinities with 0. brevipes. 



I may mention that the type of 0. doderl&mi is represented 

 by a single specimen of very large size ; the diameter of the disk 

 given by Loriol is 31 mm. I have never had any specimen of 

 O. brevipes which reached these dimensions, and Loriol himself 

 states that the diameter of the disk of 0. brevipes is between 7 and 

 27 mm. It is rather curious that Loriol, after describing O. doder- 

 leini in 1899, compared it only with 0. scolopendrina, and did not 

 dream of discussing its affinities with O. brevipes. But these affinities 

 are in reality very close. However, at least three characters seem 

 to me to separate the two forms ; first the ornamentation of the disk, 

 then the relative size of the arms, and lastly the number of arm 

 spines. The ornamentation of the disk was described by Loriol, 

 and his type shows well the small black spots which involve not only 

 the granules but also the underlying plates. Loriol compares these 

 spots to a sort of oscula, which is evidently an exaggeration, for we 

 have to do here with a simple color change, as is evident from the 

 somewhat enlarged photograph which I give (pi. 72, fig. 3) of a 

 fragment of the dorsal surface of the disk of O. doderleini. These 

 little spots are arranged very irregularly on both surfaces of the 

 disk, but they all have almost the same dimensions ; I find that each 

 of them is surrounded by a lighter circle, a feature which Loriol did 

 not notice. Whatever may be the ornamention and the coloration of 

 the disk of O. brevipes I have never seen, and no one has ever de- 

 scribed this character. 



A feature which immediately strikes one on examining 0. doder- 

 leini is the remarkable width of the arms, a width which results both 

 from the development of the arms themselves without the arm spines, 

 and from the length of the latter. Although Loriol's type is very 

 large, the diameter of the disk reaching 31 mm., the width of the 

 arms is certainly greater than it would be in an 0. brevipes in which 

 the disk had the same diameter. I have unfortunately not had at 

 hand specimens of this species of which the disk reached that size, 

 and perhaps such do not exist ; Loriol gives as the maximum diameter 

 of the disk in O. brevipes 27 mm. I have in my own collection sev- 

 eral specimens of O. brevipes from Mauritius which may be consid- 

 ered as rather large, and the diameter of their disks varies between 

 26 mm. and 27 mm. One of these is shown on plate 72 as figure 7 ; 

 the width of the arms with the spines quite erect is about 12 mm. at 

 the place where the width is greatest, that is to say a few segments 

 beyond the disk. In 0. doderleini this width reaches 17 mm. If 



55269 22 Bull. 100 21 



