NATURAL SCIENCES OF PHILADELPHIA. 419 



ARCADE. 



20. Grammatodon inomatus, Meek <fe Hayden. 



Area (Cucullosa) inornata, M. & H. March 1858, Pr. Acad. Nat. Sci. Phila. 51. 



PECTENID.E. 



21 . Pecten extenuatus, M. & H. May 1860, Pr. Acad. Nat. Sci. Phila. 184. 



OSTREAD^E. 



22. Ostrea <_Gryphaea?) c a 1 c e a 1 a, Rcemer, ii. 25, t. 18, fig. 19. 



BRACHIOPODA. 

 LINGULID.E. 



23. Lingula brevir os tra, M. & H.March 1858, Pr. Acad. Nat. Sci. Phila. 50. 



24. Rhynchonella ? 



RADIATA. 



E CHINODERMA TA. 



PENTACRINID^E. 



25. Pentacrinus asteriscus, M. &H. Mar. 1858, Pr. Acad. Nat. Sci. Phila. 49. 



CRETACEOUS SPECIES. 



ARTICULATA. 



ANNELIDA. 



TUBICOLA. 



26. Serpula ?tenuicarinata, M. &H. Mayl857, Pr. Acad. Nat. Sci. Phil. 134. 



MOLLUSCA. 



CEPHALOPODA. 



TEUTHID^E. 



27. Thylloteuthis subovatus, M. & H.Mayl860, Pr. Acad. Nat. Sci. Phil. 175. 



BELEMNITID^E. 



28. Belemnitella b u 1 b o s a, M. & H. March 1856, Pr. Acad. Nat. Sci. Phila. 70. 



NAUTILHLE. 



29. Nautilus Dekayi, Morton, 1834, Synop. Or. Rem. 33, pi. 8, fig. 4, and 



pi. 13, fig. 4. ' 



AMMONITID^l. 



30. * Ammonites percarinatus, Hall & Meek, 1854, Mem. Am. Acad. Arts 



aud Sci. Boston, v. N. S. pi. iv. fig. 2. 



*This species was first figured and described from young, or immature specimens, 

 which differ remarkably from the adult. We have subsequently s< en individuals of 

 various sizes, which lead us to think it will probably prove to be identical with A. Woolgari, 

 of Mantell, from the English chalk. 



I860.] 



