OPHIURANS OF THE PHILIPPINE AND ADJACENT WATERS. 323 



close to O. scolopendrina, and authors have already many times 

 raised the question whether it should be considered as a distinct 

 species or reduced to the status of a simple variety of the latter. In 

 recording it among the littoral ophiurans collected by the Siboga, I 

 did not separate it specifically from O. scolopendrina, and in that I 

 followed the example of many of my predecessors, Ludwig, Mark- 

 tanner, and Doderlein. This point of view has not been accepted 

 by H. L. Clark ('08, p. 296), who considers 0. erinaceus as a very 

 distinct species, though he writes a little further on in the same 

 memoir (p. 297) : " I shall not be surprised if more extended observa- 

 tion carried on at the shore proves that erinaceus, schonleini, scolo- 

 pendrina, and wendtii are merely intergrading forms of a single 

 variable species." 



I looked into the question again in studying the rather numerous 

 specimens of Ophiocoma scolopendrina collected by the Albatross, and 

 I finally arrived at the conclusion that in spite of the rather extensive 

 variations of O. scolopendrina, 0. erinaceus may always be distin- 

 guished from it; I may even add that I have always been able to 

 distinguish the two easily and that I have never hesitated an in- 

 stant in referring a given specimen either to 0. scolopendrina or to 

 O. erinaceus. It is true that the distinctive characters have an 

 entirely secondary significance. The most obvious, or so it seems to 

 me, is afforded by the granulation of the disk, which stops in an 

 extremely abrupt manner at the periphery without passing over 

 to the ventral surface in O. erinaceus, while in 0. scolopendrina a 

 more or less extensive portion of the ventral surface is always found 

 to be covered with granules. In the first species the under arm 

 plates never have the distal border notched, the spines are stout and 

 robust, the dorsal spine is elongated and often thickened, and it is 

 always more robust and more developed than in 0. scolopendrina; 

 the tentacle scales number two throughout the greater part of the 

 length of the arms; the arms always maintain a certain rigidity. 

 The coloration is black on both surfaces of the disk, and the spines 

 are not ringed as is often the case in 0. scolopendrina. 



It is indubitable that none of these characters have any great sig- 

 nificance, but it must be recognized that some other species of the 

 genus Opliwconia are not better characterized; for instance, 0. 

 aethiops Liitken has no characters very much more distinctive, and 

 it is better differentiated by its place of origin than by its morpho- 

 logical features. As H. L. Clark has stated in the sentence which 

 I have quoted above, the names erinaceus, schonleini, and wendtii 

 perhaps only apply to forms of a single very variable species, but as, 

 0. schonleini and O. wendtii are not distinguished from 0. scolopen- 

 drina by characters more marked than those which separate these 

 from 0. erinaceus it is evident that if a specific name is to be applied 



