MONOGRAPH OV JAPANESE OPHIÜEOIDEA. 123 



Sagami Sea; 420-775 fathoms (Lyman). 



! Lat. 46° 40' S., long. 37° 50' E.; 310 fathoms (Lit^ian). ! Lat. 

 50° 10' S., long. 74° 42' E,; 175 fathoms (Lyman). 



Opliiacantltella acontoiyhora (Clark). 



Opldomitj-a acontopJiora : Clark, Biül. U. S. Nat. Miis., LXXV, 1911, 

 p. 190, %. 88. 



Off Kiirile Is.; 229 fathoms (Claek). 



Bering Sea. Alaska. Off Aleutian Is.; 1,213 fatlioms (!) 

 (Claek). 



This species appears to be distinguished fi'om the genotype, 

 0. troscheli (Lyman, 1878), by the total absence of the disk 

 granules, by the more numerous disk spines, which have a few 

 denticles near the tip, by the fewer oral papillae and arm spines, 

 and by the smaller dorsal arm plates, which are not in contact 

 with each other. I consider that, it is more natural to refer this 

 species to the present genus than to any other known one. 



Revision of Ophiothamnus, s. ext. 



It is a wonder that, the present genus has been long left in 

 a great confusion. As far as I can judge, those species which 

 have been referred to the present genus by modern systematists 

 correspond to a type, which was not considered to be Ophiothamnus 

 by Lyman, while certain species, which must be congeneric with 

 Lyman's type of Ophiothamnus, have been referred to various other 

 genera. For example, the so-called " Ophiothamnus " of modern 

 systematists includes Opkiomitra exigua Lyman, 1879 (referred to 

 Ophiothamnus by Verkill, 1899), Ophiothamnus lœvis Lütken & 

 MoETENSEN, 1899, 0. stultus Kœhlee, 1904, &c., while the genuine 

 Ophiothamnus, referred to other genera by modern systematists, 



