NOTES AND EXPIANATIONS. 



(CRETACEOUS.) 



3 = Planularia ciineata, Morton, Jour. Acad. Nat. Sci. VIII, 214, pi. 



xi, fig. 5. 



4 = Palmula sagittaria, Lea, Am, Phil. Soc. 1833, Contrib. Geol. pi 



vi, p. 218. Dr. Carpenter unites Cristellaria, Flahellina, Den- 

 talina, Nodosaria, &c. as members of a single genus, for which 

 lie uses the name Nodosarina. It may be at least convenient 

 however, to retain these names in a subgeneric sense ; but, in 

 either case, we should think Montfort's older name Phonemus, 

 should stand for the entire group. 



6 and 7 — I have not been able to find by whom these two species were 

 described, but believe it was by Ehrenburg. 

 8 = Orbitulites texanus, Roemer, Kreid. Vou. Tex. 86. 

 12 = Grammostomum phyllodes, Ehrenburg. 



168 ^Plagiostoma echinatum, Morton, Synop. Org. Rem. (Add. Obs.) 

 Ifci35. — 3 = Spondylus capax, Conrad, Jour. Acad. Nat. Sci. 



II, sec. ser. 1850, 274, xxiv, 8. 



171 = Ctenoides acutilineata, Conrad, Jour. Acad. Nat. Sci. sec. ser. 



III, 329, xxiv, 2. 



173 = Ctenoides denticulata. Gabb, Proc. Acad. Nat. Sci. Oct. 1861, 327. 



175 = Plagiostoma pelagicum, Morton, Synop. Org. Rem. 1834, 61, v, 2. 



177 = Ctenoides squarrosa, Utaeb, Proc. Acad. Nat. Sci. Nov. 1860, 366. 



195 = SYNCYCLONEMA, Meek. Type Pectenrigida, Hall&Meek, 

 Mem. Am. Acad. Arts and Sci. Boston, V, new ser. 381, ii, 4, 

 a, b, c (not Sowerby, 1818). The type of this group is a very 

 small, nearly equivalve, ovate -siiborbicular, compressed shell, 

 with small, flat, slightly unequal ears, and closed margins. 

 Hinge short ; surface with fine, obscure concentric strise, and 

 sometimes on the right valve, small rounded concentric ridges. 

 Some of the larger smooth Cretaceous and Jurassic species 

 may possibly also belong to this group. None of the so-called 

 Fectens, of the Cretaceous or older rocks, belong properly to tho 

 genus Pectet), Miiller, as typified by the recent P. maximus, Linn. 



201 ^ Leda bisulcata, Meek & Hayden, Proc. Acad. Nat. Sci. Phila. Dec. 

 1861, 440. 



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