65 American East Coast Arcas 65 



Zool. Han-ard, vol. 9, p. 122, 1S81; vol. 12, p. 241, pi. 8, figs. 3, 3a, 18S6; U. S. Nat. 

 Mus., Bull. 37, p. 42, pi. 8, figs. 3, 3a, 1889; Wagner Free Inst. Sci., Trans., vol. 3, p. 

 659, 1898), recent from Barbados and Grenada, has the dimensions: Ion. 9.7s, alt. 6.0, 

 max. diam. 5.0; Ion. of hinge-line, 6.0 mm. It is "slightly inequilateral, nearly equivalve, 

 moderately evenly inflated, whitish, with little or very fugacious epidermis; sculpture 

 very remarkable, consisting, first, of very even, broad, rounded, regular, concentric 

 waves (twelve or thirteen in number), separated by sharp, deep grooves. In dead or 

 worn shells these waves are smooth, or nearly so, but in perfectly fresh (and especially 

 young) shells on the surface of the broad slightly flattened waves may be seen what look 

 like two rows of subcylindrical, slightly irregular grains of sand, arranged side by side, 

 with their longer axes radiating from the beak ; these granules, if so they may be termed, 

 are really hollow, and are the thinnest possible bubbles of shelly matter which leave, 

 when rubbed off by any slight friction, a couple of zigzag slightly elevated lines where 

 their bases were fixed to the shell; a very slight friction will obliterate this, and then the 

 shell will be nearly smooth * * *; the narrow furrow for the ligament goes straight 

 across to the margin from the beak (which is nearly opposite the middle of the hinge- 

 line) instead of obliquely * * *." 



Area pedunculoides -S>C3.cch\; Plate XVI, Figures g, 10, 11; (Scacchi, Not. Conch, 

 foss. Gravina m Ann. Civ. due Sicil., vol. 6, p. 82, 1834; Broegger, Norges Geologiske 

 Undersoegelse, no. 31, pi. 13, figs. 17a, 17b, 1901; var. orbiadata Dall; Plate XVI, Fig- 

 ure 8; Dall, Bull. Mus. Cornp, Zool. Harvard, vol. 9, p. 121, 1881; vol. 12, p. 240, pi. 

 8, fig. 5, 1886; U. S. Nat. Mus., Bull. 37, p. 42, pi. 8, fig. 5, 1889; var. cremtlata Verrill, 

 Trans. Conn. Acad., vol. 5, p. 575, 1S82; Scapharca {Bathyarca) pectunculoides Dall, 

 Wagner Free Inst. Sci., Trans., vol. 3, pp. 619, 659, 1898), belongs to Bathyarca. Its 

 range is given by Dall as from Norway to St. Vincent. It is a well-known European 

 species and is found as a fossil. The shell is thin, with fine radiating and concentric 

 lines; left valve shghtly larger; cardinal area wider in front of the beaks; ligament oc- 

 cupying only the posterior part of the cardinal area; teeth oblique, in two series, with a 

 gap opposite the beaks; anterior part of the shell with a shallow sulcation extending to a 

 notch in the ventral margin; inner margin smooth. 



Dall says that the American specimens are shorter and rounder than those from far- 

 ther east in the Atlantic sea-bed and the Norwegian and Arctic seas. He described a 

 nearly round variety from the Gulf of Mexico as variety (7r(^i'c«/rtAi. " Area grenophia 

 Risso may be this species, but it was not figured, and the description is quite insufficient. 

 Area pectinicidoides var. crcnulata Verrill, appears to have the form of var. orbiculata, the 

 teeth of the Gulf specimens above mentioned, the marginal crenulations of glomerula, 

 and the sculpture of the type oi pectunculoides." — Dall. 



Area glaeialis Gra.y; Plate XVI, Figures 12, 13, 14; (Gray, Parr\-'s First Voyage, 

 Supp. to App., p. 244, 1824; Bjoerlykke, Norges Geologiske Undersoegelse, no. 25, p. 69, 

 fig. I, 189S; Broegger, 1. c, no. 31, p. 120, pi. 6. figs. 1-4, 1901; Friele and Grieg, Nor- 

 wegian Xorth-Atlantic expedition, vol. 7, Mollusca 3, p. 19, 1901), is found recent in the 

 Arctic seas and has been reported south to New England. It is also found in the Pleis- 



