502 



LAMELLIBRANCHIA TA. 



[PHO. PI.A. 



shumardanus, Winchell, 1865, Proc. Acad. 

 Nat. Sci. Phil., p. 126, and Geo. Sur. 111., 

 vol. 2, p. 453, Kinderhook Gr. 

 PHOLADELLA, Hall, 1870, Prelim. Notice 

 Lam. Shells, p. 63. [Ety. diminutive 

 of the recent genus Pholas.~] Equivalve, 

 elongated ; valves inflated ; beaks an- 

 terior, incurved ; basal margin con- 

 stricted ; escutcheon and lunule; sur- 

 face ribbed. Type P. newberryi. 



constricta, Hall, 1883, Pal. N. Y.", vol. 5, 

 pi. 78, figs. 26-27, Ham. Gr. 



cuneata, see Promacrus cuneatus. 



decussata, Hall, 1883, Pal. N. Y., vol. 5, 

 pi. 78, fig. 28, syn. for Promacrus cun- 

 eatus. 



newberryi, Hall, 1870, Prelim. Notice 

 Lam. Shells, p. 65, and Pal. N. Y., vol. 

 5, pi. 78, fig. 25, Waverly Gr. 



FIG. 891. Pholadella newberryi. 



ornata, Hall, 1870, Prelim. Notice Lam. 



Shells, p. 64, syn. for P. radiata. 

 parallela, Hall, 1883, Pal. N. Y., vol. 5, pi. 



78, figs. 22-24, Ham. Gr. 

 radiata, Conrad, 1842, (Nuculites radiatus,) 



Jour. Acad. Nat. Sci., vol. 8, p. 248, 



and Pal. N. Y., vol. 5, pi. 78, figs. 15-21, 



Ham. Gr. 

 truncate, Hall, 1870, Prelim. Notice Lam. 



Shells, p. 64, syn. for P. radiata. 

 Pholadomya el&ngata, see Allorisma elonga- 



tum. 

 PHTHONIA, Hall, 1870, Prelim. Notice Lam. 



Shells, p. 70. Equivalve, elongate-ovate, 



wider posteriorly ; beaks obscure ; sur- 

 face radiated and concentrically marked ; 



no teeth ; ligament external. Type P. 



sectifrons. 

 cylindrica, Hall, 1883, Pal. N. Y., vol. 5, 



pi. 78, figs. 1-4. Ham. Gr. 

 lirata, Hall, 1883, Pal. N. Y., vol. 5, pi. 78, 



fig. 14, Ham. Gr. 

 nitida, Hall, 1885, Pal. N. Y., vol. 5, p. 



477, Chemung Gr. 

 nodocostata, Hall, 1870, Prelim. Notice 



Lam. Shells, p. 71, and Pal. N. Y., vol. 



5, pi. 78, figs. 5-9, Ham. Gr. 



FIG. 892. Phthonia sectifrons. Left valve. 



sectifrons, Conrad, 1842, (Cypricardites 

 sectifrons,) Jour. Acad. Nat. Sci., vol. 

 8, p. 245, and Pal. N. Y., vol. 5, pi. 78, 

 figs. 10-13, Ham. Gr. 



truncate, Hall, 1885, Pal. N. Y., vol. 5, p. 



476, Chemung Gr. 



PINNA, Linnaeus, 1758, Syst. Nat. 10th Ed. 

 [Ety. pinna, a wing.] Shell long, tri- 

 angular equivalve ; beaks terminal, 

 pointed; posterior end broad, trun- 

 cate, gaping; a subtrigonal, posterior 

 muscular impression, 'and a small reni- 

 form one at the beaks; cartilage long, 

 narrow, internal, supported by a slen- 

 der ridge close within the cardinal 

 edges; no teeth; shell of one internal 

 laminated layer, and an external ver- 

 tically fibrous layer. Type P. squa- 

 mosa. A living genus that sometimes 

 attains a length of two feet, and ranges 

 from low water to sixty fathoms. It 

 moves vertically, partly buried in 

 sand, with knife-like edges erect. The 

 byssus has been mixed with silk, spun 

 and knit into gloves. 



adamsi, syn. for Pinna peracuta. 



consimilis, Walcott, 1885, Monogr. U. S. 

 Geo. Sur., vol. 8, p. 236, Subcarbon- 

 irerous. 



hinrichsana, White & St. John, 1868, 

 Trans. Chi. Acad. Sci., p. 122, St. 

 Louis Gr. 



inexpectans, Walcott, 1885, Monogr. U. S. 

 Geo. Sur., vol. 8, p. 235, Subcarbon- 

 iferous. 



ludlovi, Whitfield, 1876, in Ludlow's Car- 

 roll to Yellowstone Park, p. 143, Coal 



marshallensis, Winchell, 1865, Proc. Acad. 

 Nat. Sci., p. 126, Marshall Gr. 



FIG. 893. Pinna squamosa. 



maxvillensis, Whitfield, 1882, Ann. N. Y. 

 Acad. Sci., vol. 2, p. 221, Kaskaskia Gr. 



missouriensis, Swallow, 1863, Trans. St. 

 Louis Acad. Sci., vol. 2, p. 97, Kaskas- 

 kia Gr. 



peracuta, Shumard, 1858, Trans. St. Louis 

 Acad. Sci., vol. 1, p. 214, and Pal. E. 

 Neb., p. 198, Coal Meas. 



stludovici, Worthen, 1883, Geo. Sur. 

 111., vol. 7, p. 326, St. Louis Gr. 



subspatulata, Worthen, 1875, Geo. Sur. 



111., vol. 6, p. 524, Warsaw Gr. 

 Pinnopsis, syn. for Lunulicardium. 



acutirostra, syn. Lunulicardium ornatum. 



arnatus, see Lunulicardium ornatum, 

 Placunopsis, Morris & Lycett, 1853, Monogr. 

 FOBS. Great Oolite. [Ety. Placuna, a 

 genus; opsis, resemblance.] Suborb- 

 icular, upper valve convex, radiately 

 striated or taking the form of the sur- 

 face to which it adheres ; lower valve 

 flat ; ligamental groove submarginal : 

 muscular impression subcentral. Type 

 P. jurensis. Not a Palaeozoic genus. 



