PTE.] 



LAMELLIBRANCHIA TA. 



507 



undulata, Meek & Worthen, 1868, Geo. 

 Sur. 111., vol. 3, p. 456, Kinderhook Gr. 



varistriata, Billings, 1866, Catal. Sil. Foss. 

 Antic., p. 50, Anticosti Gr. 



volans, Winchell & Marcy, 1865, Mem. 

 Bost. Soc. Nat. Hist., p. 95, Niagara Gr. 

 PTERINOPECTEN, Hall, 1883, Pal. N. Y., vol. 

 5, pt. 1, p. 3. (Plates and Explana- 

 tions.) [Ety. Pterinea, a genus; Pec- 

 ten, a genus.] Valves more or less 

 convex; radiated and bearing concen- 

 tric lines of growth; hinge-line long, 

 straight; wings not well defined, being 

 simple expansions of the upper lateral 

 margins to the hinge-line. Type P. 

 undosus. 



FIG. 904. Pterinopecten undosus. 



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



pt. 1, p. 66, Ham. Gr. 

 crenicostatus, Hall, 1884, Pal. N. Y., vol. 



5, pt. 1, p. 78, Chemung Gr. 

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



pt. 1, p. 62, Marcellus Shale, 

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



pt. 1, p. 76, Chemung Gr. 

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



1, p. 77, Chemung Gr. 

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



pt. 1, p. 61, Marcellus Shale, 

 fllitextus, Hall, 1884, Pal. N. Y., vol. 



5, pt. 1, p. 67, Ham. Gr. 

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



pt. 1, p. 64, Ham. Gr. 

 hoosacensis, Walcott, 1885, Monogr. 



U. S. Geo. Sur., vol. 8, p. 232, 



Subcarboniferous. 

 imbecilis, Hall, 1884, Pal. N. Y., vol. 



5, pt. 1, p. 75, Chemung Gr. 

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



pt. 1, p. 59, Up. Held. Gr. 

 intermedius, Hall, 1884, Pal. N. Y., 



vol. 5, pt. 1, p. 68, Ham. Gr. 

 invalidus, see Aviculopecten in- 



validus. 

 fcetus, Hall, 1884, Pal. N. Y., vol. 5 ; 



pt. 1 , p. 63, Marcellus Shale, 

 multiradiatus, Hall, 1884, Pal. N. Y., 



vol. 5, pt. 1, p. 57, Up. Held. Gr. 

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



pt. 1, p. 79, Chemung Gr. 

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



1, p. 60, Up. Held. Gr. 

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



1, p. 58, Up. Held. Gr. 

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



pt. 1, p. 70, Ham. Gr. 



spio, Walcott, 1885, Monogr. U. S. Geo. 



Sur., vol, 8, p. 233, Subcarboniferous. 

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



pt. 1, p. 65, Ham. Gr. 



FIG. 905. Pterinopecten undosus. 



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



1, p. 74, Chemung Gr. 

 suborbicularis, Hall, 1843, (Pterinea sub- 



orbicularis,) Geo. Rep. 4th Dist. N. Y., 



p. 264, and Pal. N. Y., vol. 5, p. 80, 



Chemung Gr. 



terminalis, see Aviculopecten terminalis. 

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



1, p. 72, Ham. Gr. 



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



pt. 1, p. 71, Ham. Gr. 

 PTERONITELLA, Billings, 1874, Pal. Foss., vol. 



2, p. 141. [Ety. diminutive of Pte.ro- 

 nites.] Resembles Rerinea, but pos- 

 sesses in front of the beaks several 

 small, anterior, cardinal teeth, and close 

 beneath the hinge-line several more or 

 less elongated posterior teeth. Type P. 

 venusta. 



curta, Billings, 1874, Pal. Foss., vol. 2, p. 

 143, Low. Held. Gr. 



FiG.906. Pteronitella venusta. b, Hinge-line. 



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

 p. 143, Low. Held. Gr. 



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

 p. 142, Low. Held. Gr. 



PTERONITES, McCoy, 1844, Syn. Carb. Foss. 

 Ireland, p. 81. [Ety. pteron, a wing.] 

 Subtriangular, depressed, hinge-line as 

 long as the shell; beaks terminal, or 

 nearly so, forming a very narrow, ob- 



