MONOGRAPH OF JAPANESE OPHIUROIDEA. 343 



aa — Disk bearing spines, or both granules and spines .... Opidomastix. 



AA — Disk covered by a naked skin, entirely free of granules and 

 spines Ophiarthrum. 



Key to Japanese species and varieties of Ophioconia, 



A — Interbracliial ventral surfaces entirely covered with granules ; oral 

 shields usually oval; dorsal arm plates with clearly cut outer 



border ; arm spines shorter dorsally than ventrally hrevipes. 



AA — Granulations of the interbrachial ventral surfaces not extending to 

 the abradial border of the genital shts, the inner parts being mostly 

 naked ; oral shields quadrangular ; outer border of the dorsal arm 

 plates not clearly cut ; arm spines longer dorsally than ventrally . . 



scolopendrina. 



a — Disk variegated; arm spines annulated typical scolopendrina. 



aa — Disk as weU as arm spines uniformly black. 



h — Arm spines not very short and stout ; two tentacle scales to each 



pore var. erinaceus. 



hb — Arm spines exceedingly short and stout ; a single tentacle scale to 

 each pore, except in a few basal arm joints var. schœnUinii. 



Ophiocofiia brevipes Petees. 



Ophiocoma hrevipes : Peters, Arch. Naturg., 1852, j)- 85^^; Lyman, 

 Rep. Challenger, V, 1882, p. 172 ; Marktanner-Turneretschee, Ann. K. K. 

 Natm-h. Hofmus. Wien, II, 1887, p. 303 ; Bell, Proc. Zool. Soc. London, 

 1888, p. 388; Döderlein, Zool. Jahrb. Sys., Ill, 1888, p. 831; Loriol, 

 Mém. Soc. Phys. d'Hist. Nat. Genève, XXXH, 1894, p. 25, PL XXIH, fig. 

 4 ; Döderlein, Semon - Zool. Forschungsr., V, 1896, p. 289 ; Kœhler, Exp. 

 Siboga, XLV, Pt. 2, 1905, p. 61 ; Kœhler, Bull. Sei. Fr. Belg., XLI, 1907, 



1) This paper was not seen by me. 



