298 PROCEEDINGS OF THE AMERICAN ACADEMY 



Blast., p. 84, Taf. 2, fig. 9, a -c; Hall, Iowa, Vol. 1, p. G93, 



PI. 25, fig. 1 6. Pentremites, n. sp., D. D. Owen, Sill. Journ., 



Vol. 43, 1824, p. 20, fig. 3. Suhcarboniferous. Kaskaskia 



limestone, Iowa. 

 P. RcEMERi, Sliumard, 1855, 2d Rep. Geol. Missouri, Part 2, p. 



186, PI. B, fig. 2, a- d. Devonian. Chemung group. 

 P. Reinwardtii, Troost, Trans. Geol. Soc. Penn., Vol. 1, p. 224, 



PL X. Pentatremitites Reinwardtii, Roemer, 1852, Monogr. 



Blast., p. 52, PI. 3, fig. 18, a-c. F. Roemer, Leonhard and 



Bronn, Jahrb., 1848, p. 296. Silurian. Lower Helderberg 



group. 

 P. Sati, Sliumard, 1855, 2d Rep. Geol. Survey of Missouri, Part 



2, p. 185, PI. B, fig. 1, a— d. Svhcarhoniferous. Encrinital 



limestone. 

 P. STELUFORMis, Owen and Sliumard, 1850, Journ. Acad. Nat. Sci. 



Philad., New Series, Vol. 2, p. 67, PI. 7, fig. 16, a, b ; Geol. 



Survey of Wisconsin, Iowa, and Minnesota, p. 593, PI. 5 



A, fig. 16, a, b. Suhcarboniferous. Encrinital limestone. 

 P. SUBTRUNCATUS, Hall, lowa, Vol. 1, p. 485, PI. 1, fig. 3. Devo- 

 nian. Hamilton group. 



P. SULCATUS, Roemer, 1852. Pentatremitites sulcatus, Monogr. 

 Blast., p. 34, Taf. 3, fig. 10, a-c. Suhcarboniferous. Ar- 

 chimedes limestone. 



P. STJiMETRicus, Hall, lowa, Vol. 1, p. 694, PI. 25, fig. 14. Sub- 

 carboniferous. Kaskaskia limestone. 



P. TRUNCATA, Conrad, Proceed. Acad. Nat. Sci. Philad., Vol. 1, p. 

 334. Suhcarboniferous. 



P. Verneuili. See Ducleocrinus Verneuili. 



P. WoRTHENi, Hall, Iowa, Vol. 1, p. 606, PI. 15, fig. 1. Suhcar- 

 boniferous. Keokuk limestone. 



PETRASTER, Billings, 1858, Geol. Survey of Canada, Palasont., 

 Dec. III. p. 79. Silurian. Trenton limestone. 

 P. RiGiDUS, Billings, 1. c. p. 80, PI. 10, fig. 3. Palasterina rigidus, 

 Geol. Rep. 1856, p. 291. Silurian. Trenton limestone. 



PLATYCRINUS, Miller, 1821. 



P. Americanus, Owen and Shumard, Journ. Acad. Nat. Sci. 

 Philad., 2d Series, 1851, p. 89, PI. 11, fig. 1, a, b ; Geol. 

 Survey of Wisconsin, Iowa, and Minnesota, p. 594, PI. 5 



B, fig. 1, a, b. Subcarboniferoiis. Burlington limestone. 



