NATURAL SCIENCES OP PHILADELPHIA. 423 



APORRHAID^l. 



90. Aporrkais Americana, Evans & Shumard sp. 



Rostellaria Americana, E. & S. 1857, Trans. St. Louis Acad. Sci. i. 42. 



91. Aporrkais Nebrascensis, Evans & Skumard, sp. 



Rostellaria Nebrascensis, E. & S. Aug. 1854, Pr. Acad. Nat. Sci. Pkila. 164. 



92. Aporrkais suble vat a, M. & H. May 1860, " " 178. 



93. Aporrkais biangulata, Meek & Hayden, 



Rostellaria biangulata, M. & H. Marcb 1856, Pr. Acad. Nat. Sci. Pkila. 65. 

 Aporrkais biangulata, M. & H. May 1860, " " 185. 



:")4. Aporrkais par va, M. & H. 1 " " " 178. 



LITORINID^E. 



95. Fossar? Nebrascensis, Meek & Hayden. 



Natica ambigua, M. & H. Marcb 1856, Pr. Acad. Nat. Sci. Pkila. 66. 

 (Non Fossar ambiguus, Lin. sp.) 



NERITOPSID^E. 



96. Neritopsis? Tuomeyana, Meek & Hayden. 



Natica Tuomeyana, M. & H. Nov. 1856, Pr. Acad. Nat. Sci. Pkila. 270. 



TROCHID^E. 



7. Margarita Nebrascensis, Meek & Hayden. 



Turbo Nebrascensis, M. & H. Marck 1856, Pr. Acad. Nat. Sci. Pkila. 64. 

 Margarita Nebrascensis, M & H. May 1860, " " 185. 



98. *Margaritella flexi striata, Evans & Skumard sp. 



Solarium flexistr latum, E. & S. Aug. 1854, Pr. Acad. Nat. Sci. Phila. 163. 



DENTALIAD^E. 



99. Dentalium g r a c i 1 e, H. & M. 1854, Mem. Am. Acad. Arts, and Sci. Boston, 



v. N. S. pi. 3, fig. 11. 



100. Dentalium pauperculum, M. & H. May 1860, Pr. Acad. Nat. Sci. 



Pkila. 178. 



TECTURID^E. 



101. Tectnra o cci d en tal i s, Hall & Meek, sp. 



Capulus occidentalis, H. & M. 1854, Mem. Am. Acad. Sci. and Arts, Boston, v. 

 N. S. p. 385, fig. 13. 



102. Tectura ? parva, Meek & Hayden (manuscript.) 



103. Tectura? papillata, Meek & Hayden. 



Capulus fragilis, M. & H. Marck 1856, Pr. Acad. Nat. Sci. Pkila. 68. 

 (Non Tectura fragilis, Gray & Gamard.) 



104. Anisomyon borealis, Morton sp. 



Hipponyx borealis, Morton. 1842, Jour. Ac. Nat. Sci. Pkila. viii. pi. 11. fig. 6. 

 Helcion carinatus, M. & H. Marck 1856, Pr. Acad. Nat. Sci. Pkila. 68. 

 Anisomyon borealis, M. & H. Jan. 1860, Am. Jour. Sci. xxviii. 2d ser. 35. 



105. Anisomyon Shumard i, Meek & Hayden (manuscript). 



* We propose to establish a new genus, under the name of Margaritella, for the 

 reception of many pearly Jurassic and Cretaceous shells usually referred to Solarium. 

 It is evident from the pearly lustre, and other characters of these fossil shel!s, that they 

 do not even belong to the same family as our recent typical species of the genus Archi- 

 tectonica (= Solarium.) The above species may be regarded as the type of the genus. 



I860.] 



