RECENT OPHIURANS. 273 



tinctly longer than wide. Side arm-plates low and small with seven glassy, 

 thorny spines, of which the longest about equals three joints. Tentacle-scale 

 rather large for an Ophiothrix. Color (dried), dull purplish blue; outer ends of 

 radial shields and the upper arm-plates somewhat variegated with whitish; a 

 distinct median white stripe bordered with somewhat darker purplish blue marks 

 on the upper side of the arm, and distally the upper margin of each side arm- 

 plate is also whitish; under arm-plates purplish, with a broad median white 

 stripe ; oral region pale yellowish ; arm-spines and disk spines glassy or whitish. 



HoLOTYPE (M. C. Z. 2481). Fiji Islands or Samoa; locality doubtful. 

 Received from Museum Godeffroy. 



This specimen combines so well the characters of 0. trilineata and of 0. 

 longipeda (or one of its close allies) that it is not at all unlikely it is a hybrid 

 (hence the name). The disk is very much like that of trilineata but has more 

 spinelets, while the arm-plates and spines are more like those of longipeda; the 

 coloration is also suggestive of the latter, while the length of the arms is quite 

 intermediate between the two. Since the two species occur abundantly on the 

 same reefs, their hybridization is not impossible but I am not willing to affirm 

 it on the strength of one specimen. 



828. 0. HYLODES H. L. Clark, 1911. Bull. 75 U. S. N. M., p. 263, f. 130. 



6 specimens, including 1 paratype. Japan: Ayukawa; Tokyo Bay. 

 China Sea, near Pulo Sapatou. 



829. O. KOREANA Duncan, 1879. Journ. Linn. soc. Zool., 14, p. 473. H. L. Clark, 1911. Bull. 



75 U. S. N. M., p. 260, f. 127, 128. 



92 specimens. Korea Strait, 59 fms. Japan: Hakodate Bay, 15.5 fms.; 

 Sea of Japan, 79 fms. ; off Cape Tsiuka, 44-47 fms. ; southwest of Goto Islands, 

 139 fms.; off Kagoshima Gulf, 103-152 fms.; off eastern coast, 52-77 fms.; 

 Uraga Channel, 70-197 fms. ; Suruga Gulf, 78-131 fms. ; mouth of Bay of Yeddo. 



830. 0. LINEATA Lyman, 1860. Proc. Boston soc. nat. hist., 7, p. 201. Plate 12, f. 4. 



7 specimens, including the holotypb. Florida: east coast; Miami; 

 off Sand Key, 20 fms. 



831. O. LIODISCA, sp. nov. (Xeios, smooth + diaKos, disk). Plate 12, f. 3. 



Disk 6 mm. in diameter; arms 30-35 mm. long. Disk flat and perfectly 

 smooth (hence the name), covered with a coat of rather large scales, the central 

 one largest; there are 9-10 series between center and interradial margin and 

 about 5 series across interradial area between radial shields. Interbrachial 



