294 ART. 2. — H. MATSUMOÏO : 



Ophiozonella Matsumoto, 1915. 



Disk covered with stout plates mingled with smaller ones. 

 Radial shields large, usually separated from one another, but 

 sometimes slightly in contact in pairs. Oral and adorai shields 

 rather stout. Four or five oral papilla? on either side of each 

 jaw ; the outermost one is pointed inwards above the next papilla, 

 which is the largest. Teeth arranged in a single vertical row. 

 Dental papillae absent. Genital slits not reaching to the disk 

 margin. Arms short, very stout at base, rather rapidly tapered 

 outwards to very slender extremities. Dorsal, as well as ventral, 

 arm plates more or less rhomboidal, not very widely in contact or 

 mostly separated from one another. Two to four arm spines, 

 short, lying flat on the arm. One or two tentacle scales to each 

 pore. 



This genus includes (1) species with two tentacle scales 

 to each pore, viz., Ophiozona nivea Lyman, 1875, 0. tessellata 

 Lyman, 1878, 0. marmorea Lyî^ian, 1883, 0. dypeata Lyman, 1883, 

 0. hlspinosa Kœhleb, 1897, 0. molesta Kœhlek, 1904, 0. elevata 

 Clark, 1911, 0. platydisca Claek, 1911 ; (2) species with one 

 tentacle scale to each pore, viz., 0. insuJaria Lyman, 1868, 0. 

 stellata Lyman, 1878, 0. antillarum Lyman, 1878, 0. depressa 

 Lyman, 1878, 0. alba Lütken & Moktensen, 1899, 0. contigua 

 LtJTKEN & MoETENSEN, 1899, 0. casttt Kœhler, 1904, 0. depressa 

 var. media Kœhler, 1904, 0. projecta Kœhler, 1905, 0. longispina 

 Clark, 1908, 0. pokjplax Chxmi, 1911, and 0. (/*«//?wirt Mortensen, 

 1913, the genotype being 0. loiir/ispina. 



Key to Japanese species of Ophioxonella. 



A — Two tentacle scales to each pore. 



