146 



o rugulis concontricis undulatis. ot striis, sub lente 

 conspicuis, radiantibiis. tenciTiiiiis, postcrius cvanidis, 

 confertissime et minutissitiie aliitacoa; intus alba. Um- 

 bones prominuli, medii. Mar<iiiics simpliccs; anticus 

 jequaliter curvatus, vcntralis pono iiicdiutn subrectus, 

 postice arcuatim adscendens, doin b'vit<'r sinuatus, ot 

 sub an<;ul() vix recto, rotundato, cum iiiargine dorsali 

 conflucns, leviter arcuato. comprcsso elato, area ian- 

 ceolata, utrinque impressa. Donticuli aiitici 13, utn- 

 bonalibus tribus miiiiinis, ad 6-tum elatiores, dein bre- 

 viores, crassiores, distantiores, ultimo tubercularl; po- 

 stici 12, ad sextum elatiores, dein crassiores, brevio- 

 res, distantiores. Fovea liframenti triangularis, sequi- 

 lateralis, basi rotiindata. Loiif^. 17; lat. 11-, crass. 

 6 mill. 



Gray. Sup]>lernent to tiie Appendix to 

 P;irrj.s tirst Voyaue , 1819—20: ]i. 

 241 (1824). — Non Möller, uvc 

 MöucH. nec Saus, iiec Brodekip et 



SOWKRBY. 



Brown. Illuslr. Conch. Gr, Brit., ed. 



1. t. 2.5. f. 19 (1827). — Ed. 2, 



p. 84. t. 33. f. 19 (1844). 

 S. Wooi). Crag Moilusca, vol. II. p. 



94. t. 10. i 14. a— b. 

 FoiiuEs & Hanley, Hist. Brit. Moll. 



Vol. II, p. 233 (1853). 

 W. Woou, Ind. test., suppl , ed 1. p. 



6, t. :>, Area, f. 6 (1828), — ed. 2. 



Hanley, p. 205, t. et fig. ead. 

 Hisinger. Letliaea Suecica, ]). 60, t. 



30, f. 13 (1837). 

 MÖRCH. TillfEw till RiNK, Grimland, p. 



93 (1857).^ 

 Gray. Lifet of Brit. Anini. Brit. Mus. 



Part. VII, p 1 61 : Non vero — Area 



glaeialis, Gray, Suppl. ParrysVojage, 



'1819—20. 

 Nucula portlandica. Hitchkock, Geol. of Portland, Bost. 



fourn. Nat. hist., vol. I. p. 328, fig. 



Nucula arclica. 



Nucula truncata 



Leda truncata. 

 Area glacialis. 



Nuculana glacialis. 

 Yoldia glacialis. 



