CARBONIFEROUS AGE. 303 



_P. Godonii Defr. (P. florealh, in part), — both from the Kaskaskia limestone; P. 

 Woodmani M. & W. Fig. 573, Poteriocrinus Missouriensis Shumard, from the St. Louis 

 limestone ; Fig. 574, Actinocrinus proboscidialis H. ; Fig. 575, Dorycrinus unicornis M. 

 & W. ; Fig. 576, Zeacrinus elegans H., — this and the two preceding from the Burling- 

 ton limestone; Fig. 577, Batocrinus ChristyiM. & W., the arms fallen off, — from the 

 Encrinal limestone of Missouri ; Fig. 579, proboscis of Batocrinus longirostris H. ; Fig. 

 578, Platycrinus Saffordi Troost, side-view, from Burlington. Most of the above Cri- 

 coids have lost their arms and pedicels. The most prolific locality of Crinoids, as yet 

 known, is Burlington, Iowa, where Mr. Charles Waehsmuth has collected three hundred 

 and fifty-live species, representing forty-four genera, besides six Echinoids, four Asteri- 

 oids, and one Ophiuroid. The Keokuk beds of Crawfordsville, Indiana, yield much 

 more numerous specimens, and in more nearly perfect condition; but less than fifty 

 species have yet been found there. The genera most numerously represented are Actin- 

 ocrinus (including several subgenera), Cyathocrinus, Dichocrinus, Forbesiocrinus, Pla- 

 tycrinus, Poteriociinus, Scaphiocrinus, and Zeacnnus. 



Echinoids. — Fig. 583, Archmocidaris Wortheni H., of the St. Louis limestone; Fig. 

 584, A. Shumardana H., of the St. Louis limestone, — a spine enlarged; Fig. 584 a, 

 plate of the same species, enlarged about two diameters; Fig. 585, plate of Archmo- 

 adaris Norwoodi H., natural size, from the Chester limestone. Fig. 587, Mdonites mul- 

 tipora 0. & N., from the St. Louis limestone, the apical disc; 587 a, a portion of one of 

 the ambulacral series, enlarged two diameters; Fig. 586, Oligoporus nobilis M. &. W., half 

 natural size, from the Burlington limestone; Fig. 587 b, ambulacral plates of 0. Dance 

 M. & W., enlarged two diameters. Figures 586, 587, a, b, are from Worthen's Report 

 on the Geology and Paleontology of Illinois. The genus Archmocidaris, like the mod- 

 ern Cidaris, has large prominences on the plates, to support the spines, which are also 

 large. In Mdonites and Palteechinus, the plates are without prominences, and the spines 

 small. 



3. Mollusks. — (a.) Bryozoans. — Fig. 590, Archimedes Wortheni H., being a 

 portion of the spiral axis, with the reticulated expansion removed. Fig. 589 a, a por- 

 tion of the reticulated expansion, magnified and showing the non-poriferous surface. 

 Fig. 589 b, the poriferous side of the same. 



(b.) Brachiopods. — Fig. 598, Chonetes ornata Shum. (natural size), from the Litho- 

 graphic and Chouteau limestones, Missouri ; 598 a, enlarged surface-markings of same ; 

 Fig. 597, Spirifer biplicatus H., from Burlington and Quincy, Illinois; Sp. Keokuk H., 

 from the Keokuk beds; Fig. 591, Orthis Michelini Morr. (var. Burlingtonensis H. ), from 

 the Burlington limestone; Hemipronites crenistria Dav. (Orthis or Streptorhynchus um- 

 braculum) (Fig. 605); Fig. 592, Sjnriferina octoplicata M. ; Fig. 593, Spirifer bisulcatus 

 Sow. (increbescens H.); Fig. 594, Retzia Verneuiliana H.; Fig. 595, Chonetes variolata 

 D'Orb. ; Fig. 595 a, hinge-line of same, and aperture, closed by a pseudo-deltidium; 

 Fig. 596, Productus punctatus Mart. ; also P. Fleminyii Sow., P. elegans N. & P., Spi- 

 rifer incrassatus Eichw., Sp. spinosus N. & P., from the Chester limestone, etc. The 

 Spirifer incrassatus is confined in Missouri to the lower Archimedes limestone. Many 

 of the other Brachiopods occur not only in the Subcarboniferous, but also in the Coal- 

 measures. They are common also in Europe. 



(c.) Laniellibranchs. — Nucula Shumardana H., N. nasuta H., Cypricardina Indian- 

 ewsi'sM., Conocardium Meekanum H., all from the St. Louis limestone of Indiana, Illi- 

 nois, and Idaho; Pinna Missouriensis Swallow, of the Chester limestone of Illinois; 

 species of Yoldia, Nuculana, Myalina, Schizodus, Aviculopecten. 



(d.) Pteropods. — Species of Bellerojihon, Conularia, etc. 



(e.) Gasteropods. — Euomphalus Spergenensis H., Pleurotomaria Meekana H., and 

 many other species of these genera, as well as Platyceras, Straparollus, Naticopsis, Na- 

 tica, Bulimella, Loxonema, etc. 



if) Cephalopods. — The Cephalopods are of the genera Nautilus (N. spectabilis M. & 

 W., from the Chester, two feet in diameter), Orthoceras (0. nobile M. & W., from the 

 Chester, five to six feet long and one foot in diameter), Gyroceras (G. Burlingtonense 

 H., from Iowa, five inches in diameter), Goniatites, etc. 



