PLATYCRINIDiE. 651 



.P. clytis Hall = F. scohina Meek and W. 



P. corrugatus 0. and Shum. =^ P. discoideus O. and SnuM. 



P. currymlleiisis RowL. and Hare = P. aqiiitenms S. A. Miller. 



P. exsert2is Hall = P. hurling to^iensis 0. and Shum. 



P. Georgei Hall =: P. Sara Hall. 



P. richjieidensis Hall and Whitfield :=P. graphicus H. and W. 



P. inornatus McCh. = P. hiirJiiigtonensis 0. and Sh. 



P. lautus S. A. Miller = P. burlingtoiiensis 0. and Sh. 



P. moiiroetisls Wouthen = P. .^ttr^ Hall. 



P. multibrttchiatus M. and W. = P. discoideus 0. and Sh. 



P. nodobracUattts Hall 1861 (not 1S5S) = P. YaiideUi, Ysx. perasper. 



P. Kodosiis WiRTGEN and Zeilek = Citlicrocriuus twdosus. 



P. nodobracUatus Hall 1858 (not 1861) = P. burlingtonetisis 0. and Sh. 



P. Tiodulosits Hall (not Goldf.) =P. ornigranulus McCh. 



P. nucleiformis Hall=:P. burlingionensis 0. and Su. 



P. offa Hall 1861 (not DeK. and Le Hon 1853) = P. SaWj Shum. 



P. Owraj M. and W. = P. regalis Hall. 



P. parvus VikiAj^CordylQcrbnts plumosiis (Hall), 



P. penicilhis M. and W. = P. Huntsvill<2 Tkoost. 

 P. plam-basalis RowL. and Hake = P. quinquenodiis White. 

 \ P. planus Hall (not 0. and Sh, 1852) =P. ife/Zj Shum. 



P. plenus M. and W, =: P, Suntsvillie Teoost, 

 P. pleurommiiius White = Eucladocrimis pleurovimineus, 

 P. plumosus Hall= Cordylocriiius plmnosus (Hall). 

 P, pr{pmaturus Hall :^ Marsnpiocrinus prtematurus. 

 P. prcenuntius W, and Sp, = Eucladocrinus prcenuntius. 

 P. praitenanus M, and W, =: P. Sarie Hall. 

 P.pulcheUus S. A. Miller = P, discoideus 0, and Sh. 

 P. ramulosus Hall = Cordglocrimts ranmlosus. 

 P. rotmidus S. A. Miller = P. sculptus Hall. 

 P. shimardianus Hall = P. discoideus 0. and Sh. 

 P. striobrachiatus Hall = P. discoideus 0. and Sh. 

 P. sulcatus S, A, Miller ^ P. excavatus Hall. 

 P, iennesseensis RoEMER = Marsupiocrinus iennesseensis. 

 P. tentaculatus Hall ^ Marsupiocrinus ieutaculatus. 

 P. truncatus Hall = P. americanus 0. and Sh. 

 P. tuberosus Hall ^ Eucladocrinus iuberosus. 



Of the seventeen species in the above list which we have been unable to 

 identify, the majority were described either from the basals alone, or these 

 with the addition of the radials, and most of them from a single specimen, — 

 a practice which cannot be too severely condemned. No palajontologist at 

 the present day would undertake to describe an Actinocrinits or Batocrinus 

 from a specimen showing nothing but basals and radials ; and why should it 

 be done with Platycrinus ? There is often the greatest difficulty in defining 

 the limits of species and varieties with an -abundance of the best preserved 

 specimens in hand. The variation of surface ornamentation in Platycrinus 

 is almost without limit. The detached radials and basal plates, beautifully 

 preserved and free from matrix, have been collected by thousands from the 

 soft sandy layers of the Lower Burlington limestone, and it would be possible 



