314 A. E. Verrill — North American Ophiuroidea. 



Amphioplus, gen. nov. (See p. 306.) 

 Table of the species of Amphioplus from the West Indian region. 

 C. — Tentacle-scales present. 



h. — Two tentacle-scales. 



i. — Oral papillae four to six, in a series; one or two are distal oral 

 tentacle-scales. Arm-spines usually three, sometimes four. 



j. — Dorsal and venti'al arm-plates, at base of arms, in contact. 

 Radial shields narrow, separated, or barel}^ touching. Arm- 

 spines three. 



A. tumida (Lym. '78) Ver. Disk swollen ; radial shields linear. 



W. I., 321 fath. 



*^, ahdita Verrill, "72. Radial shields lunate, parallel, middle arm- 

 spine stouter, flattened, obtuse. Four oral papillae. Long I. Sound. 



^A. macilenta Ver. Five oral papillae. Spines all slender. 



East Coast U. S. 



A. nereis (Lym. '83) Ver. Oral papillae five, thick, unequal ; 

 genital scale with a row of papillje. W. I., 148 fath. 



A. Agassizii Ver., p. 315. Oral papillae six, slender, the two dis- 

 tal ones larger. W. I., 424 fath. 



jj. — Dorsal arm-plates scarcely joined. Radial shields narrow and 

 in contact distally. Five small, bead-like oral papillae. 



A. cuneata (L^^m. "78) Ver. Three slender arm-spines. W. Indies. 



ii. — Four (varying sometimes to three) oral papillae. Arm- 

 spines, three or four. Radial shields a little separated dis- 

 tally, divergent. Oral shield pelecoidal, acute proximally. 

 Disk-scales do not form a rosette. 



A. duplicata (Lym. '75) Ver. First under arm-plate often double; 

 adoral shield narrow. W. Indies. 



JiJi^ — One tentacle-scale. Radial shields widely separated. Five 

 unequal oral papillae. 



A. Stearnsi (Ives) Ver. W. Indies. 



CC. — No tentacle-scale. Four oral papillae. Four arm-spines. 

 Radial shields touch distally. 



A. Verrillii (Lym. '79) Ver. Radial shields rather large, diver- 

 gent. Disk-scales form a rosette. W. Atlantic, 2650 fath. 



Many extralimital species of Amphioplus have been described. 

 Among them are the following : 



