CLARK: BRITTLE-STARS. 337 



p. 8, pi. 2, fig. 1, 2) described as a young Ophioderma and which I, 

 without seeing it, named Ophiocryptus hexacanthus (1915. Journ. 

 ent. zool., 7, p. 64). Comparison with the smallest specimens of 

 Ophioderma cinereum in the M. C. Z. shows that Koehler was right 

 and the specimen is a young Ophioderma, and probably 0. cinereum. 

 Although it and my Tobagoan specimen are of the same size, they 

 differ in so many points that they are probably not identical. It 

 seems better to describe and figure this specimen and give it a name, 

 than to let it sink out of sight in literature under the name Ophio- 

 derma. It is quite possible that it will ultimately be shown that 0. 

 duhius is a young Ophioderma, and that the same is true of 0. macu- 

 latiis and Ophioncus, but the truth will be more speedily reached if 

 the distinctive names are retained. 



OPHIOLEPIDIDAE. 



Ophioplocus bispinosus, sp. nov. 

 bispinosus = having two spines, in reference to the number of arm-spines. 



Plate 4, fig. 2. 



Holotype.— M. C. Z. 4,025 and 6 Paratypes, M. C. Z. 4,054, 4,211. 

 Victoria: Philip Island, Westernport, May, 1915. Joseph Gabriel 

 coll. 



Disk, 9 mm. in diameter; arms about 25 mm. long. Disk very flat, 

 slightly lobed in the interradii, covered by a coat of small, more or 

 less swollen scales, about 7 or 8 series in each interradial area; no 

 primary plates are visible but at the margin, in each interradius, is a 

 conspicuous, slightly projecting plate, much larger than any other 

 disk-plate and more than twice as wide as long (or high). Radial 

 shields small (no larger than some disk-plates), widely separated, 

 slightly sunken. Outside radial shields and extending on to the base 

 of the arm are a number of small, swollen plates. Arm-segments 

 covered dorsally by a set of six plates, of which the three distal are 

 much larger than the three proximal; of the distal three, the lateral 

 are largest and (judging from conditions at tip of arm) represent the 

 two halves of the original upper arm-plate; of the three proximal 

 plates, the median is largest; not infrequently, by what seems to be 

 fusion, the proximal series consists of but two plates or even one; 



