122 THE VOYAGE OF H.M.S. CHALLENGER. 



Opliiactis simjjlex, Ltk. {OjMoleins), Acldit. ad Hist,, part 2, p. 130, 1859 ; L}Tn., 

 111. Cat. Mus. Comp. ZooL, No. i. p. 105. 



Ophiolepis simplex, Le Conte, Proc. Phil. Acad., vol. v. p. .318, Nov. 185L 

 OpMactis Orstedii, Ltk., Addit. ad Hist., part 2, p. 129, 1859. 

 Opliiactis arenosa (?), Ltk., Addit. ad Hist., part 2, p. 129, 18-59. 



West Coast Central America. 



OpMactis arenosa, Ltk., Vid. Meddel., p. 25, March 1856 ; Addit. ad Hist., part 2, 

 p. 129. Vll., Trans. Conn. Acad., vol. i., part 2, p. 266. 

 West Coast Central America. 



OpMactis hroyeri, Ltk., Vid., Meddel., March, 1856, p. 24 ; Addit. ad Hist., part 2, 



p. 130; Lym., 111. Cat. Mus. Comp. ZooL, No. i. p. 108; ^^1., Trans. Conn. Acad., 



vol. i., part 2, p. 264. 



Ophiolqns atacamensis, Pliilippi, Reise durch der Wueste Atacama, p. 190, 1860. 

 Opliiactis atacamensis, Ljn., Oph. Viv. Of. Kong. Akad., p. 324, 1866. 



Opliiactis frat/ih's, Ljn., Om nfigra nya arter, Opli. Of. Kong. Akad., p. 164, 1866; Opli. Viv. 

 Of. Kong. Akad., p. 324, 1866. 



Isla Blanca, Chili ; West Coast of Central America ; Hawai. 



OpMactis nigrescens, Hutt., Ech. New Zealand, 1872, p. 2. 

 New Zealand. 



OpMactis maculosa, v. Mart., Wieg. Archiv, vol. xxxvi. p. 248, 1870. 

 China Sea. 



OpMactis abyssicola, Ljn., Oph. Viv. Of. Kong. Akad., p. 324, 1866. 



Amphiura ahjssieola, Sars, Oversigt Norges Echin., p. 18, 1861. 

 Opliiocnida dbyssicola, Lym., 111. Cat. Mus. Comp. Zool., No. i. p. 12. 



Norway; 190 to 400 fathoms. 



AmpMura. 



Ampliiura, Fbs., Linn. Trans., vol. xix., 1842. 



Disk small and delicate, covered with naked, overlapping scales, and furnished with 

 uncovered radial shields. Teeth. No tooth papillae. Mouth angles small and narrow, 

 and bearing a few (usually four or six, rarely eight or ten) small mouth papillce. Arms 

 long, slender, even and more or less flattened. Arm spines short and regular. Two 

 genital openings to each interbrachial space. 



Amj)Mura hellis gives a good type of this generic structure. The disk wall is cased 

 with fine, regular, overlapping scales and large, flat, elongated radial shields, having at 

 their outer end a small knob which marks their articulation to the long, slender, flattened 

 cluli-headed genital plate. To this last is fastened an equally long, slender, blade-like 



