500 



LAMELLIBRANCHIA TA. 



[PAN. PAR. 



flabellum, Hall, 1884, Pal. N. Y., vol. 5, 



pt. 1, p. 240, Oriskany Gr. 

 recurva, Hall, 1884, Pal. N. Y., vol. 5, pt. 

 1, p. 241, Up. Held. Gr. 



PAL^OSOLEN, Hall, 1885, Pal. N. Y., vol. 5, 

 p. 46. [Ety. palaios, ancient; Solen, a 

 genus.] Shell in form like Solen; dor- 

 sal and ventral margins subparallel ; 

 anterior end short, rounded ; poste- 

 rior end elongate, truncate; gaping; 

 beaks small, appressed ; cardinal line 

 straight; umbonal slope prominent; 

 surface concentrically marked. Type 

 P. siliquoideus. 



siliquoideus, Hall, 1870, (Orthonota sili- 

 quoidea,) Prelim. Not. Lam. Shells, p. 89, 

 and Pal. N. Y., vol. 5, p. 483, Ham. Gr. 



PANENKA, Barrande, 1881, Syst. Sil. d. 1. 

 Boheme, vol. 6, p. 128. Equivalve, in- 

 equilateral, elliptical or subcircular, 

 beaks prominent, incurved ; cardinal 

 line straight or arcuate; test thin; sur- 

 face concentrically lined, 

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



423, Ham. Gr. 



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



416, Up. Held. Gr. 

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



419, Marcellus Shale. 



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



424, Ham. Gr. 



dichotomy Hall, 1885, Pal. N. Y., vol. 5, 



p. 416, Schoharie grit, 

 elevata, Conrad. 1848, (Monotis elevata,) 



Proc. Acad. Nat. Sci., vol. 3, p. 23, Che- 



mung Gr. 

 equilatera, Hall, 1885, Pal. N. Y., vol. 5, 



p. 419, Marcellus Shale, 

 hero, Hall, 1885, Pal. N. Y., vol. 5, p. 418, 



Marcellus Shale, 

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



420, Marcellus Shale. 



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



420, Marcellus Shale, 

 multiradiata, Hall, 1885, Pal. N. Y., vol. 



5, p. 417, Up. Held. Gr. 

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



422, Ham. Gr. 

 poulsoni, Conrad, 1848, (Monotis poul- 



soni,) Proc. Acad. Nat. Sci., vol. 3, p. 



23, Chemung Gr. 

 radians, Conrad, 1842, (Pterinea radians,) 



Jour. Acad. Nat. Sci., p. 252, and Pal. 



N. Y., vol. 5, p. 422, Ham. Gr. 

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



421, Ham. Gr. 



robusta, Hall, 

 1885, Pal. N. 

 Y., vol. 5, p. 

 424, Portage 

 Gr. 



speciosa, Hall, 

 1843,(Avicula 

 speciosa, ) 

 Geo. Rep. 4th 

 Dist. N. Y., 



FIG. 884. Panenka speciosa. 



p. 243, Portage Gr. 

 ventricosa, Hall, 1885, Pal. N. Y., vol. 5, 

 p. 417, Marcellus Shale. 



Panopsea, Menard de la Groye, 1807, Ann. 

 du Mus. 9. [Ety. mythological name.] 



cooperi, see Chaenomya cooperi. 

 PARACARDIUM, Barrande, 1881, Syst. Sil. 

 de la B)heme, vol. 6, p. 137. [Ety. 

 para, allied to; Cardium, a genus.] 

 Equivalve, inequilateral, subcircular or 

 subelliptical; posterior side subtrun- 

 cate ; surface marked with fine radii 

 and concentric striae ; the margin of a 

 small cardinal area under the beaks is 

 crenulated. 



doris, Hall, 1885, (Cardiola doris,) Pal. 



N. Y., vol. 5, p. 428, Portage Gr. 

 PARARCA, Hall, 1885, Pal. N. Y., vol. 5, p. 36. 

 [Ety. para, allied to ; Area, a genus.] 

 Equivalve, inequilateral, transversely 

 subelliptical or rhomboidal; anterior 

 end short, rounded ; cardinal line about 

 half the length of the valves, arching 

 at the beaks; surface marked by radii 

 and concentric striae; hinge narrow, 

 with a series of minute crenulations. 

 Type P. venusta. 



erecta. Hall, 1885, (Cardiola erecta,) Pal. 

 N. Y., vol. 5, p. 432, Waverly Gr. 



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

 432, Waverly Gr. 



prtecedens, Hall, 1885, Pal. N. Y., vol. 5, 

 p. 429, Up. Held. Gr. 



sao, Hall, 1885, (Cardiola sao,) Pal. N. Y., 

 vol. 5, p. 430, Chemung Gr. 



transversa, Hall, 1885, (Cardiola trans- 

 versa,) Pal. N. Y., vol. 5, p. 429, Che- 

 mung Gr. 



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



431, Chemung Gr. 



PARACYCLAS, Hall, 1843, Geo. Hep. 4th 

 Dist. N. Y., p. 171. [Ety. para, allied to ; 

 Cyclas, a genus.] Equivalve, subequilat- 

 eral, suborbicular or subelliptical; ante- 

 rior end regularly rounded; posterior end 

 rounded or subtruncate, more produced 

 than the anterior; beaks small and 

 low; hinge-line short, post-cardinal slope 

 sometimes subalate; surface marked 

 concentrically; ligament supported in- 

 terually on each side by a narrow 

 plate, which leaves in the cast two di- 

 verging grooves directed forward from 

 the beak ; muscular impression on the 

 post-umbonal slope; pallial line a little 

 within the margin of the shell. Type 

 P. elliptica. 



billingsana, S. A. Miller, 1883, 2d Ed. Am. 

 Pal. Foss., p. 311, Devonian. Proposed 

 instead of Lucina occidentalis, Billings, 

 1859, Assiniboine and Sas. Ex. Exped., 

 p. 187, figs, b and c, which name was 

 preoccupied. 



chemungensis, Hall, 1885, Pal. N. Y., vol. 

 5, p. 443, Chemung (Jr. 



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

 72, figs. 37 to 41, Schoharie grit. 



elliptica, Hall, 1843, Geo. Rep. 4th Dist. 

 N. Y., p. 171, and Pal. N. Y., vol. 5, pi. 

 72, figs. 23-30, Cornif. Gr. 



elliptica var. occidentalis, Hall & Whit- 

 field, 1872, 24th Rep. N. Y. Mus. Nat. 



