106 ART. 2.— H. MATSÜMOTO : 



OpJiioniitrella polyacantlia (Claek). 



OpMomitra pohjacantha : Clark, Bull. U.S. Nat. Mns., LXXV, 1911, 

 p. 187, fig. 86. 



Eastern Sea ; 103 fathoms (Clakk). 



Ophiophthalmus, g. uov. 



Disk covered with more or less imbricating, irregular scales, 

 and may be beset with coarse granules. Eadial shields naked, 

 rounded or oval. Three to six oral papillœ on either side. Teeth 

 arranged in a single vertical row. Dental papillae absent. Dorsal 

 arm plates in contact with each other in the basal arm joints. 

 Numerous arm spines, long, conical, opaque, hardly serrate, never 

 approximating dorsalty. Usually a single large, flat, leaf-like 

 tentacle scale to each pore. 



This new genus includes Ophiacantha normani Lyman, 1879 

 (referred to OpUiomitra by Lyman, 1882), OpMomitra granifera 

 LüTKEN & MoETENSEN, 1899, Opliiacanthci rellcta Kœhlee, 1904, 

 Ophlomitrella miitata Kœhler, 1904, 0. languida Kœhlee, 1904, 0. 

 2olacida Kœhlee, 1904, OpJiiomitra microphyJax Claek, 1911, 0. 

 codonomorpha Claek, 1911, Ophiacantha leucorhahdota Claek, 1911, 

 0. eurypoma Claek, 1911, 0. hylacanlha Claek, 1911, Ophiomitrella 

 amcricana Kœhlee, 1914, &c., besides the genotype, Ophiacantha 

 cataleimmoida Claek, 1911. 



The present genus is very nearly allied to Ophiomitrella, but 

 differs from it in the comparatively well developed dorsal arm 

 plates, the basal ones being in contact with each other, and in 

 the arm spines not approximating dorsally in the basal arm joints. 

 Further, this genus differs from the genuine Ophiacantha in the 

 short and rounded radial sliields and in the coarser disk scales. 



