NORTH PACIFIC OPHIURANS IN NATIONAL MUSEUM CLARK. 195 



lat. 31 IS' 30" N.; long. 130 42' E., 85 fathoms, 1 specimen. Bathy- 

 metrical range, 85 to 152 fathoms. Temperature range, 56 to 52.9. 

 Twenty-eight specimens. 



Type.C&t. No. 25588, U.S.X.M., from station 4933. 



This very fine species is distinguished from the other members of 

 the genus by the huge radial shields, which cover most of the disk, 

 the very long, smooth, upper arm spines and the peculiar oral shields. 

 It is probably nearest to 0. rugosa Koehler, from the Dutch East 

 Indies. 



Family OPHIACANTHID.E. 



With the probable exception of the Ophiolepididse, there is no 

 group of Ophiurans so much in need of revision as those which are 

 commonly included under this family designation. The preceding 

 family (Ophiohelidse) is a most unnatural group as proposed by 

 Perrier (1891 ) a and as used here, for Ophiomitra and Ophiocamax, are 

 very close to true Ophiacantha, and Ophiotholia is an almost unique 

 genus of doubtful relationships. Verrill b has divided the Ophia- 

 canthidse into a large number of genera, many of which, to say the 

 least, are valid and worthy of recognition. But some of the charac- 

 ters, of which he makes use, seem to me of doubtful value, and in 

 many cases I have found it hard to see the lines which he has drawn. 

 Lack of time prevents my going into the subject at present with the 

 thoroughness which it demands, and I am therefore reluctantly com- 

 pelled to ignore Verrill' s genera for the present and use Ophiacantha in 

 a very wide sense. I have also stretched Ophiolebes to include a 

 number of diverse forms, but in spite of using these two genera to 

 their widest extent, it has been necessary to establish some new genera. 

 It is hoped that the figures and descriptions given will atone in some 

 measure for leaving the group even more chaotic than it was before. 



OPHIACANTHA BIDENTATA. 



Asterias bidentata RETZIUS, Diss. Ast., 1805, p. 33. 



Ophiacantha bidentata LJUNGM AX, Ofv. Kon.Vet.-Akad. Forh., vol. 28, 1872, p. 652. 



Localities. Albatross station 4781, Bering Sea, lat. 52 14' 30" N.; 

 long. 174 13' E., 482 fathoms, fine gray sand, pebbles, bottom temper- 

 ature 38.6, 1 specimen; station 4804, off Kurile Islands, lat. 46 42' X. ; 

 long. 151 47' E., 229 fathoms, coarse pebbles, black sand, bottom 

 temperature 35. 9(?),1 specimen; station 481 2, off Sado Island, lat. 38 

 33' N.; long. 138 40' E., 176 to 200 fathoms, fine brown mud, bottom 

 temperature 34.9, 3 specimens; station 4818, off Sado Island, lat. 38 

 8' 55" N.; long. 138 31' 30" E., 225 to 245 fathoms, fine brown mud, 

 bottom temperature 33.7, 51 specimens; station 4819, off Sado 



a Verrill used the same name in 1899 as though ignorant of Perrier 's proposed family. 

 b Trans. Conn. Acad., vol. 10, 1899, pp. 319-357. 



