234 ART. 2. — H. MATSUMOTO : ' 



the disk, short or moderately long, very stont, widest at the 

 base, rapidly tapering outwards, only horizontally flexible. Arm 

 plates either all well developed, or the dorsal and ventral ones 

 may be very rudimentary. Arm spines short, lying flat on the 

 arm. Tentacle scales variable in number, leaf-like, rarely absent. 



This family is very extensive and includes thirty -eight genera, 

 which may be grouped into two subfamilies as follows. 



Subfamily 1. Ophiomastinœ Matsumoto, 1915 : — Second oral 

 tentacle pores opening outside the oral slits. 



I. Several basal lateral arm plates extraordinarily widened ; 

 genital slits invisible or very insignificant ; disk covered 

 merely with primaries and radial shields. 

 Astrophlura Sladen, 1878. 

 Ophiophycis Kœhler, 1901. 

 Ophiomisidium Kœhlee, 1914. 

 Ophiotypa Kœhlee, 1897. 

 OphiomastiK Lyman, 1878. 

 II. Basal lateral arm plates not much widened ; genital slits 

 usually large ; disk covered usually with both primaries 

 and secondary scales, besides the radial shields. 

 Haplophiura Matsumoto, 1915. 

 AntJiopJdura Clark, 1911. 

 Aspklophiura Matsumoto, 1915. 

 Ophlopyrgus Lyman, 1878. 

 Stegophiura Matsumoto, 1915. 

 Amphiophiura Matsumoto, 1915. 

 Gymnophiura Lütken & Moktensen, 1899. 

 Opliiosteh'a Bell, 1902. 

 Ophiochrysis Koehlek, 1904. 

 Homalopldura Claek, 1915. 



