OF ARTS AND SCIENCES. 287 



AGELACRINUS, Vanuxem, 1842. 



A. DiCKSONi, Billings, Geol. Survey of Canada, Palaeont., Dec. III. 



p. 84, PI. 8, fig. 3, 3 a, 4, 4 a. Silurian. Trenton limestone. 

 A. Habiiltonensis, Vanuxem, Geol. 3d Dist. New York, p. 306, 



158. Devonian. Hamilton group. 

 A. Kaskaskiensis, Hall, Iowa, Vol. 1, p. 696, PI. 25, fig. 18. 



Suhcarhoniferous. Kaskaskia limestone. 



AMYGDALOCYSTITES, Billings, 1854. 



A. FLOREALis, BiUings, Canadian Journal, Vol. 2, p. 270 ; Survey 

 Eeport, 1856, p. 289 ; Palaeontology, Dec. III. p. 63, PI. 6, 

 fig. 1, a — e. Silurian. Trenton limestone. 



A. TENUiSTRiATUS, Rep. Geol. Survey of Canada, 1857, p. 289; 

 Canad. Journ. Vol. 2, p. 271 ; Palaeont., Dec. III. p. 64, 

 PI. 6, fig. 2 a, 2 b. Silurian. Lower Silurian. 



A. RADiATUS, Rep. Geol. Survey of Canada, 1857, p. 289; Canad. 

 Journ., Vol. 2, p. 271 ; Palaeont., Dec. III. p. %b, PI. 6, fig. 

 3, a, b. Silurian. Trenton limestone. 



APIOCYSTITES, Forbes, 1848. 



A. ELEGANS, Hall, Nat. Hist, of New Y'ork, Palaeontology, Vol. 2, 

 p. 243, PI. 51, fig. 1 - 17. Compare A. pentremoides, Forbes, 

 Mem. Geol. Soc. of Great Britain, 1848, Vol. 2, Part. 2, 

 p. 502, PI. 45. Silurian. Niagara group. 



ARCHEOCIDARIS, McCoy. Echinocrinus, Volborth, 1832. 

 Pal^ocidaris, Desor. 



A. ACULEATUS, Shumard, Trans. Acad. St. Louis, Vol. 1, No. 2, 

 1858, p. 223. Coal measures. 



A. Agassizi, Hall, Iowa, Vol. 1, p. 698, PI. 26, fig. 1, a-d. Suh- 

 carhoniferous. Burlington limestone. 



A. BIANGULATUS, Shumard, Trans. Acad. St. Louis, Vol. 1, Part 2, 

 p. 224. Middle coal measures. 



A. Keokuki, Hall, Iowa, Vol. 1, p. 699, PI. 26, fig. 2, a, b. Suhcar- 

 honiferous. Keokuk limestone. 



A. MEGASTYLUS, Shumard, Trans. Acad. St. Louis, Vol. 1, Part 

 2, p. 225. Upper coal measures. 



A. NoRWOODi, Hall, Iowa, Vol. 1, p. 701, PI. 26, fig. 5, a-e. 

 Suhcarhoniferous. Kaskaskia limestone. 



A. Shumardiana, Hall, Iowa, Vol. 1, p. 699, PI. 26, fig. 3, a - d, 

 Suhcarhoniferous. "Warsaw limestone. 



