Systematic Classification of Paleozoic Echini, including one Triassic Genus, based on the Structure and Growth of the Ambulacra and Interambulacra, and the Peristome. 



*P. iiieeki, Jackson, 6 or more A., fi I. 

 P. irregularis, M. and \V., (5 or more A., J-b 1. 



= PHOLIDOCIDAEIS, M. and W., or more A 5 or m 

 I Plates highly irregular. Subcarbomtero 



i (nr perhaps 20?) A., 4-5 1. 



, III A., 6-7 1. 

 hill ;iiia Miller), 10 A., ol. 



I=I,EPIDESTHES, M. and W., S-18 (or perhaps 20?) A., 

 I 4-7 1. Plates regular. Suhcarboniferous. 



LEPIDESTHID/E, .Tackson, 6-18 (or 20?) A., 3-G I. Peristome 



Ismail. No 1. plates resorbed. Plates of corona 

 iiiiliricated. Plates regular or irregular. 



•Jf. ...,i 



M. 1,1,1 



(Russia) M. ,li,: 



P. minohemis, Worthcn and Miller, 2 A., 5 or more I. 

 *lEu.) P. hiscridils, M'Co3^ 2 A., 5 I. 



I 



!= I'ERISCHODOMUS, M'Coy, 2 A., 5 or more I. .Suhcarboniferous, Carbonifer. 



» J sq,mmomg, M. and W., 2 -|- A., S I. 

 I 



•(Eu.) L. miillr-n, Schultze, 2 A. ,11 I. 

 (Eu.) L. rlieuanm, Beyr., 2 A., 5 I. 



*R. (irnciUs, (M. and VV.), 2 A., S I. 

 *R. Im-lmgloiimsh, (M. and W.), 2 A,, G I. 

 *(Eu.) Jl. ekgims, (M'Coy), 2 A., 5 I. 



LEPIDOCENTKUS, .Toh. Muller, 2 A., 5-11 1.- 



Fam. LEPlDOCE:NTRID/E.Lov.5n,2A.,5-llI. Peristome 

 I small, with no I. plates resorbed. I. plates 



* OLIGOPORUS, M. and W., 4 A., 4-1) I. Snlicarbonifc 



•(Eu.) P. tphitrim, M'Coy, 2 + A., 6-7 I. 

 •(Eu.) P. gigm, M'Coy, 2 4- A., 11 1. 



(Eu.) P. riJiplicM, M'Coy, 2 -|- A., .5 I. 



(Eu.) P. phiUiimx, Forbes, 2 + A., 5 (probably) I. 



(Eu.) P. iiitermediita, W. Keeping, 2 + A., 5 I. 



f PAL^EOHINUS, (Scouler), M'Coy, pars. 2 + A., .5-7 I. Carboniferous 1 



I' RHOECHINUS, W. Keeping, 2 A., 4-8 I. Suhcarboniferous, Carboniferous, 



n. ARCH/EOCl DARI D/E, M'Coy, 2 or 2 -(- A., 4-8 1. Peristome large, wit 

 I sevemlrowsof I. plates resorbed (/li-c/uuoct(i«m). rlati 



I of corona more or less imbricated. 



(Eu.) T. princeps, (Laube), 2 A., 3 I. 

 TIARECHINUS, Neumayr, 2 A., 3 I. Triassic. 



Order IV, PLESIOCIDAROIDA, 2 A., 3 I Peristome sm.all, with 

 ' I no I. plates resorbed. Periproct central. 



I Plates of corona not imbricated. 



Order II PERISCHOECHINOIDA, 2-14 (in one species 18, per- 

 uraei ii, rt ^^^^^^^ ^^^^^^ ^ .^^^^ ^ Peristome small, 



with iirst row of I. plates resorbed (ilfe- 

 /■„,ll,^, <>r,,i„ii,„;,x); or peristome large, 

 Willi ffviTiil rows of I. plates resorbed 

 {A,;-}!„,„-i,l„,-',i,) ; or peristome small, with 

 no I. plates resorbed {PhoJidocidaris, Lcpi- 

 dechinii,!). Periproct central. I'lates of 

 corona not imbricated or iinbricjited. 



Order III, CYSTOCIDAROIDA. (.See page 242.) 



(Eu.) B. pahkni, Schmidt, 2 A., 1 1. 

 (Eu.) B. globid,is, Eichwald, 2 A., 1 I. 



" CIDARIS, Agassiz and Desor, 2 A. A. plates simple. 2 I. Permian to Recent. 



I 



,e section compound. 

 2 (m one genua 4) i. 



OrderCIDAROIDA, 2A. A. plates simple or in one section comi»und. 2 (in one genus 4) I. 



I Peristome lar.-c \\itli t^cvfral rows of I. plates resorbed. Periproct central. 



Plates of cuM.n.i ii.il iiiil.riiiiiliicl. 



Subclass EUECHINOIDEA, 2 A. a. , , hues simple orcoinpound.2(inonegenus4)I. Only one 

 I genus, representing a single order m tins subclass, is known in the Paleozoic. 



I 'fherefore other ordera are not considered in this table. 



.BOTHRIOCIDARIS, Eichwald, 2 A., 1 I. Lower Silurii 



jrbed. Firat 



,. of A. plates retained as in embryos. Periproct central. Plates not imbricated. 



Order I, BOTH RIOCIDAROIDA, 2 A., 1 1. Peristome small, Avith no I. plates 



I , „„„, . , i» ■ 1 iiiT p„rUta,T,e «mnll w-ith no I iilate3re6orbed(Bortriori&OTS, Knrai/iimu, PMirfocitfariii, lepifcMti^^ 



Subclass PAL/EECH I NOI DEA,j2-.4^n _™e^^eci^l^^^ J^J^^^^^lT^t^^Z^.^t^lJ^^^ Periproct «nt.., or eccentric iu iHinocp,i<». Plates of corona not imbricated, or 



s of plates in each ambi 



imbriciited. This subclass is represented only m the Paleow 



;epting the order Flem 



iroida, which is Tiii 



■ambulaci 



'__— « ,-, iiiir P^rUt/MT.^ <!i,ifill with no I nlates resorbed iBoOiriocidaria, Tiarechinm, Pholidocidam, Leptdechims) ; or peristome amnll, 



ClassECHINOiPE:A,_2;UJiuor«^^spe^^^^^^^^^^ Periprict centi.1, or eccentric («.™c««,. Plates of corona not 



imbricated, or imbricated. 



