498 



LAMELLIBRANCHIA TA. 



[ORT. — PAI,. 



parvula, Hall, 1870, Prelim. Notice Lam. 



Shells, p. 88, and Pal. N. Y., vol. 5, pi. 



78, figs. 29-32, Ham. Gr. 

 phaselia, Winchell, 1863, Proc. Acad. 



Nat. Sci., p. 12, Marshall Gr. 

 pholadis, Conrad, 1838, (Pterinea phola- 



dis,) Ann. Geo. Rep. N. Y., p. 118, Hud. 



Riv. Gr. 

 rectidorsalis, Winchell, 1862, Proc. Acad. 



Nat. Sci., p. 412, Marshall Gr. 

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



481, Chemung Gr. 

 siliquoidea, see Palaosolen siliquoideus. 

 simulans, Billings, 1874, Pal. Foss., vol. 2, 



p. 131, Up. Sil. 

 (?) speciosa, Billings, 1874, Pal. Foss., vol. 



2, p. 130, Up. Sil. 

 undulata, Conrad, 1841, Ann. Rep. N. Y., 



p. 51, and Pal. N. Y., vol. 5, pi. 78, figs. 



37-42, Ham. Gr. 



Fig. 875.— Orthouota uudulata. 



venlricosa, see Spathella ventricosa. 



venusta, Billings, 1874, Pal. Foss., vol. 2, 

 p. 129, Up. Sil. 

 Obthonotklla, S. A. Miller, 1882, Jour. 

 Cin. Soc. Nat. Hist., vol. 5, p. 117. [Ety 

 orthos, straight ; rwtos, back ; ellus, di- 

 minutive.] Very small, inequilateral, 

 inequivalve, more or less elliptical ; 

 beak anterior ; surface smooth or con- 

 centrically lined ; hinge straight behind 

 the beaks ; ligament external. Type O. 



faberi, S. A. Miller, 

 1882, Jour. Cin. 

 Soc. Nat. Hist., 

 vol. 5, p. 117, Hud. 

 Riv. Gr. 

 Ostrea, Linnaeus, 1758, 

 Syst. Nat. 10th ed., 



Fig. 876.-Orthonoteila P- 696. [Ety. 08- 



faberi. Greatly en- trea, an oyster.] 



larged. Inequivalve, ir- 



regular in shape, with a single adduc- 

 tor muscle. Not a Palaeozoic genus, 

 though a species has been founded 

 upon a single valve and called 0. 

 patercula. 

 patercula, Winchell, 1865, Proc. Acad. Nat. 

 Sci., p. 124, and 4th Ann. Rep. U. S. 

 Geo. Sur., p. 288, Burlington Gr. 



PaljEanatina, Hall, 1870. Prelim. Notice 

 Lam. Shells, p. 84. [Ety. palaios, an- 

 cient; Anatina, a genus.] Transversely 

 elongate ; gaping ; left valve the larger ; 

 oblique constriction ; hook-like pro- 

 cess anterior to the beaks ; no lateral 



FIG. 877.— Pal tea nati n a 

 typus. 



teeth ; surface concentrically lined. 

 Type P. typus. 

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



p. 490, Chemung Gr. 

 quadrata, see Prorhynchus quadratum. 

 sinuata, Hall, 1885, Pal. N. Y., vol. -5, p. 



491, Chemung Gr. 

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



p. 489, Chemung Gr. 

 typus, Hall, 1870, 

 Prelim. Notice 

 Lam. Shells, p. 

 85, and Pal. 

 N.Y.,vol. 5, pi. 

 79, figs. 26-39, 

 Chemung Gr. 

 Palsearca, syn. for 

 Cypricardites. 

 saffordi, see Cypricardites saffordi. 

 ventricosa, see Cypricardites ventricosus. 

 PaljF.ocardia, Hall, 1867, 20th Rep. N. Y. 

 Mus. Nat. Hist., p. 389. [Ety. palaios, 

 ancient; kardia, a heart.] Cordiform, 

 obliquely subovate, ventricose ; urn- 

 bones gibbous ; beaks prominent in- 

 curved ; hinge-line very short ; surface 

 marked with radiating stria. Type P. 

 cordiformis. 

 cordiformis, Hall, 1867, 20th Rep. N. Y. 

 Mus. Nat. Hist., p. 389, Niagara Gr. 

 PaLjEoconcha, n. gen. [Ety. palaios, an- 

 cient; conche, shell.] Shell small, equi- 

 valve, inequilateral, oblique, varying 

 from subcircular or subovoid to mytili- 

 form ; height equal to or greater than 

 length ; closed all around ; without ex- 

 ternal evidence of ligaments ; anterior 

 side more or less truncated and round- 

 ing into the base below; beaks ele- 

 vated, projecting beyond cardinal line 

 without incurving; cardinal line 

 straight or slightly arching ; some evi- 

 dence points to an anterior and pos- 

 terior muscular scar near the ends of 

 the cardinal line; pallial line simple; 

 no lateral teeth and probably edentu- 

 lous; surface smooth. Type P. faberi. 

 faberi, n. sp. Shell small, height greater 

 than length, very slightly oblique, 

 closed all around; beaks projecting 

 high above the hinge-line without 

 incurving; sur- 

 face smooth, 

 variable in 

 size ; a large 

 specimen has a 

 height of 0.20 

 inch, and 

 length 0.14 

 inch, a small 

 specimen is 

 about two- 

 thirds less. This species is distin- 

 guished from P. obliqua by its greater 

 proportional height, more prolonged 

 beak, less oblique form, and generally 

 larger size. Collected in the upper 

 part of the Hud. Riv. Gr., at Versailles, 

 Indiana, and in Butler County, Ohio. 



Fig. 878.— Palsejo co ncha 

 faberi. Magnified 5 diam. 



