21 Echin. 
Systematic — Eoiiinoidea. 
1031 
Laganidcic Clark 45. 
Laganum depressum Clark 41 ; L. 
Medes 138. 
f Laganum with L. eldridgei, archeren- 
sis , johnsoni , floridanum, dalli sp. n. 
Cainozoic, U.S.A., Clark & Twitciiell 
U.S. Geol. Surv. 54 pp. 122, 160-164 pi. 
lxxiv figs. la-cl, 2a-d ; lxxv figs, la-d, 
2a-d, 3a-d, 4a-d. 
\Leiocidaris Clark & Tvvitohell 49. 
f Leptarbacia argutus sp. n. Mesozoic, 
U.S. A., Clark & Twitciiell U.S. Geol. 
Surv. 54 p. 53 pi. xvi figs. la-f. 
~\Lintliia with L. alabamensis , 
wilmingtonensis spp. n. Cainozoic, 
U.S.A., Clark & Twitciiell U.S. Geol. 
Surv. 54 pp. 99, 152-153, 214 pi. lxx 
figs. 3a-c, Lxxi figs, la-d, 2a-d ; L. 
Lambert 117. 
Lovenici elongata Clark 41. 
| Lovenia forbesi Gregory 86. 
\Maeropneustes with M. carolinensis 
sp. n. Cainozoic, U.S.A., Clark & 
Twitciiell U.S. Geol. Surv. 54 pp. 154- 
153 pi. Lxxi figs. 5a-d. 
Maretia alt a Clark 41. 
]Mdlita Clark & Twitohell 49. 
| Metalia Brown 20 ; M. Clark & 
Twitciiell 49. 
f Micropsia lineatua sp. n. Mesozoic, 
U.S. A., Clark & Twitciiell U.S. Geol. 
Surv. 54 p. 63 pi. xxv. figs. la-c. 
f Monostyehia australis Gregory 86. 
-j Mortonella Clark & Twitciiell 49. 
f Nucleopygus delfortriei Lambert 
117. 
\Oligopygus with 0. floridanus sp. n. 
Cainozoic, U.S.A., Clark & Twitciiell 
U.S. Geol. Surv. 54 pp. 166-169 pi. 
Lxxix figs. la-f. 
\Oligopygus Cooke 50. 
j Ortliecliinus pretiosus sp. n. 
Cainozoic, U.S.A., Clark & Twitciiell 
U.S. Geol Surv. 54 p. 118 pi. Lvi figs, 
2a-b. 
f Orlhopsis with 0. plamdata sp. n. 
Mesozoic, U.S. A., Clark & Twitciiell 
U.S. Geol. Surv. 54 p. 54 pi. xvi figs. 
2a-c. 
\Palceeehinus Chapman 24. 
Paracentrotus Herlant 96 ; Runn- 
strom 183 & 184. 
\Pedinopsts Clark & Twitciiell 49. 
\Periarehus with P. protuberans sp. n. 
Cainozoic, U.S.A., Clark & Twitohei.L 
U.S. Geol. Surv. 54 pp. 130-136 pi. Lxii 
figs. 3a-f. 
Phyllacanthus imperialis Clark 41 ; 
P. parispinus Mortensen 149. 
f Prcescutella degrangei Lambert 120. 
Prionocidaris baculosa Clark 41. 
f Psammecliinus Clark & Twitciiell 
49. 
■\Pseudodiadema Clark & Twitciiell 
49. 
Pseudoboletia maeulata Clarke 41. 
Pseudomaretia alta, Clark 41. 
• \Pygurus , Clark & Twitciiell 49 ; 
P. michelini, Odling 158. 
' \Pyrina damesi sp. n. Eocene, Italy, 
Dainelli L’ Eocene friulano Florence 
1915 ; P. Clark & Twitchell 49. 
f Salenia, Clark & Twitchell 49. 
Salmacis, Clarke 41. 
■ \Sarsella gregoryi sp. n. Cainozoic 
U.S.A., Clark & Twitchell U. S. Geol. 
Surv. 54 p. 155 lxxvii figs. 2a~d. 
■j Schizaster ottelii sp. n. Eocene, 
Italy, Dainelli L’Eocene friulano 
Florence 1915 ; S. with 8. armiger , 
floridanus , americana spp. n. Cainozoic 
U.S.A., Clark & Twitciiell U. S. Geol. 
Surv. 54 pp. 151-152, 175-176, 221, 
227 pis. lxx figs, la-d; Ixxxii figs, la- 
c, 2a-d ; S. arnaudi, Lambert 117 ; <S. 
Brown 20. 
^Scutasler, Clark & Twitciiell 49. 
f Scutella gabbi with S. g. var. n. 
tenuis, S. pabloensis sp. n. Miocene, 
California, Kew Bull. Geol. Univ. 
California 8 pp. 367-369 pi. xxxix figs. 
1-4, 6a, 6b. ; S. montanarii, graziolii , 
frattinii spp. n. Miocene, Sardinia, 
Lovisato Riv. ital. paleont. Perugia 20 
pp. 110-112 pi. ii figs. 1-3 ; S. with S. 
mississippiensis ; tuorneyi andersoni 
spp. n. Cainozoic U.S. A., Clark & 
Twitchell U. S. Geol. Surv. 54 pp. 
124-127, 182-189 pis. lix figs, la-f, 2 ; 
lx figs, la-d ; lxxxv figs. 3a-d ; S. 
marginalis, Lambert 120. — S. Clark 
40 ; Lambert 117. 
f? Seutellaster , Clark & Twitciiell 
49. 
Scutellidae, Clark 45. 
