OPHIURANS OF THE PHILIPPINE AND ADJACENT WATERS. 207 



and England. I give here photographs of the dorsal surface of 

 two of them, one from the coasts of England (pi. 35, fig. 4) and the 

 other from Belle -He (fig. 5) , and the close resemblance to the specimen 

 photographed by Doderlein will be seen. I also include photographs 

 of two specimens from South Africa, one from the Bay of Liideritz 

 (fig. 7) and the other from Saldanha (fig. 6), which I assign with- 

 out the least hesitation to O . fragilis, var. pentaphyllum. 



The two specimens of O. artistulata from station 5523 and that 

 from station 5519 show the usual coloration; in that from station 

 5517 the dorsal surface of the disk and of the arms is of a uniformly 

 violet pink color, and the longitudinal median dorsal line of the arms 

 is scarcely indicated. 



The characters which distinguish O. artistulata from O. penta- 

 phyllum, without being of great importance, do not allow of the con- 

 fusion nor of the union of the two forms. They concern principally 

 the armature of the dorsal surface of the disk, the number and the 

 arrangement of the arm spines, the relative dimensions of the disk 

 and of the arms, and the coloration. It may be added that O. 

 aristulata has generally been found at some depth, while 0. penta- 

 phyllum is a littoral form. 



The armature of the dorsal surface of the disk of O. aristulata 

 consists of elongated spines, of somewhat variable length and thick- 

 ness, but always well developed, strongly denticulated and very 

 closey crowded (pi. 97, fig. la) ; the covering which they form on 

 the disk, between the large radial shields, is uniform, and between 

 these large spines there are no club spines. These last appear only 

 at the periphery of the disk, in the interradial regions which bulge 

 outward between the arms ; these club spines are always slender and 

 more or less elongated, and they are furnished with strong, elongated, 

 and pointed teeth, which sometimes occur only on their free tip, and 

 sometimes in greater or lesser number on different parts of their length 

 (pi. 97, fig. lb and c). In O. pentaphyllum the spines on the dorsal 

 surface of the disk are always few in number, usually short and thick, 

 and the covering consists especially of club spines, which also are 

 short, thick, and conical and are not elongated except towards the 

 periphery of the disk in the interradial spaces. 



The arms are always very much longer in respect to the diameter 

 of the disk in O. ojinstulata, than in O. pentapkyllinn. The arm spines,, 

 which are in general greatly developed, rapidly attain their maximum 

 length beyond the first ventral spine; this is very short and very 

 slender; the second, which is much longer, reaches and even exceeds 

 the length of the segment; the third, which is already almost as 

 thick as those following, reaches at least the length of two segments, 

 and sometimes even three. The following spines are still larger. 

 This increase from the first ventral spine to the second, and from 



