A. £J. Verrill — North American Ophiuroidea. 365 



Ophioplus Verrill, Opbinr. Bahama Exped. , p. 70, 1899. 

 Type, Hemieuryale tuberculosa Lymau. 



Disk email, pentagonal, thick, covered with small, thickened or 

 tubercular scales. Radial shields large, naked, separated. Oral 

 shields and adoral shields well developed and naked. Oral papillae 

 in regular series. No tooth-papilla?. Under arm-plates rather large. 

 Upper arm-plates entire, swollen and well formed, separated by a 

 transverse row of small, tubercle-like plates. Side arm-plates prom- 

 inent, separated above by a supplementaiy lateral plate. Arm- 

 spines short, two or three in a row. Tentacle-scale single. A pair 

 of small, round genital pores under the outer end of the oral shields. 



This genus differs decidedlj^ from Hemieuryale, to which it is 

 allied, in having distinct and well formed dorsal arm-plates. It is 

 also closely allied to Sigsheia. In fact, it stands between these two 

 genera in several characters. 



Ophioplus tuberculosus (Lym.) Ver. 



Hemieuryale tuberculosa Lyman, Bull. Mus. Comp. Zool., vol. x, p. 276, pi. 



vili, figs. 120-127, 1883. 

 Ophiomusium (?) Nutting, Narrative, p. 78. 



Ophioplus tuberculosus Ver., Opliiur. Bahama Exped., p. 71, pi. i, figures 

 1-16, 1899 (description). 



Plate XLIll. Figures 6-6d. 



Color deep brown, variously spotted with whitish, imitating the 

 colors of Gorgonella to which it clings. 



Usually many of the more prominent verruciform plates of the 

 upper side of the arms and disk are white ; iinder arm-plates dark 

 brown. 



Taken by the Blake Expedition in 96 and 115 fathoms ; Bahama 

 Expedition, Station 15 and 16, off Havana, 200 fathoms. 



Sigsbeia murrhina Lyman. 



Sigsbeia murrhina Lyman, Bull. Mus. Comp. Zool., v, 9, p. 234, 1878, pi. 

 iii, figs. 55, 58; op. cit., x, p. 277; Lyman, Report Voy. Challenger, Zool., 

 Ophiuroidea, v, p. 250, pi. xliii, tigs. 4-6, 1882, anatomy ; Three Cruises of 

 the Blake, ii, p. 114, fig. 399, 1888. Nutting, Narrative, p. 79. Verrill, 

 Oph. Bahama Exp., pp. 72, 73, pi. ii, figs. 1, la, 1899 (Young, description.) 



Plate XLII. Figure 7. 



This si:)ecies clings to gorgonians, which it imitates by the form 

 of its arms and the tuberculated surface of the disk, and probably 

 also in color, when living. Our figure represents a young specimen, 

 which differs considerably from the adult. 



Trans. Conn. Acad., Vol. X. October, 1899. 



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