20.2 
INDEX TO FAMILIES, ETC., 
PAGE 
Ophiukella, Milleri, Agassiz ; see Opliioderma Milleri, Phillips. 
„ nereida 156 
Ophiueid.*;, Wright ....... 138, 186 
Ophiukoidea, Wright ....... 131, 138 
Ophiomyxa, Miiller ^ Troschel ...... 133, 135 
Oreastek, Midler ^ Troschel . . . . . . .48 
„ turritus, Linck (Upper Surface of) . . . . . . & 
Othilia, Gray . . . . . . . . .42 
Pal^aster, Hall . . , . . . . 22, 24 
„ asperrimus, Salter (P.F.) . . . . . . 24 
„ coronella, Salter (P.F.) . . . , . . ; .25 
„ birudo, Forbes (P.F.) . . . . . . . 25 
„ matutinus, Hall (P.F.) . . . . . . .36 
„ Niagarensis, Hall (P.F.) . . . . . 22, 25 
obtQsus, Forbes (P.F.) . . . . . . 22, 24 
„ Ruthveni, Forbes (P.F.) . , . . . .25 
Pal^ocoma, Salter . . . . . . , 23, 29, 134 
„ Colvini, Salter (P.F.) . . . . . . .30 
„ cygnipes, Salter (P.F.) . . . . . . .30 
„ Marstoni, Salter (P.F.) . . . . . . .30 
„ Milleri, d'Orbigny ; see Ophioderma Milleri, Phillips. 
Pae^odiscus, Salter . . . . . . . 23, 35 
ferox, Salter (P.F) . . . . . . .35 
Palasterina, 3I'Ooi/ . . . . . . . 23, 26 
„ antiqua, Eisinger (P.F.) . . . . . 26, 36 
,, primaeva, Forbes (P.F.) . . . . . .26 
„ rugosa, Billings (P.F.) . , . . . .27 
„ stellata, Billings (P.F.) . . . . . .27 
Paimipes, Linck . . . . . . . 40, 44 
Patiria, Gray . . . . . . . . .45 
Paulia, Gray ..... . . . .41 
Pectinura, Forbes . . . . . . . . 133 
Pentaceros, Linck , . . ... . 39, 41 
Pentacerotid^, Crray . . . . . . . .41 
Pentabactylosasteb, Linck, pp. 39, 46 ; see Echinaster and Scytaster. 
Pentagonaster, Linck . . . . . . . 39, 42 
Petalaster, Gray . . . . . . . .41 
Petraster, Billings . . . . . . . 23, 29 
„ rigidus, Billings (P.F.) . . . . . . .29 
Plumaster, Wright . . . . . . . 112, 185 
„ ophiuroides, Wright . . . . . . .112 
Porania, Gray . . . . . . . . .44 
Protaster, Forbes . . . . . . 23, 31, 134, 136 
„ leptosoma, Salter (P.F.) . . . . . . .33 
„ Miltoni, Salter (P.F.) . . . . . . .32 
Salteri, Sowerby (P.F.) . . . . . . .33 
„ Sedwickii, Forbes (P.F.) . . . . . . .33 
