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Show 362 Genus PHOLADOMYA, Sowerby. PHOLADOMYA SUBELONOATA, Meek. Plate 2, figs. 1 and 1 a. Pholadomya dubelongata, Meek ( 1857), Trans. Albany Institute, ir, 42. Shell transversely oblong- oval, rather elongated and depressed; valve* gibbous, particnlarly in the umbonal region; anterior side very short and abruptly rounded: posterior side rounded or subtruncated, and more or less gaping; basal margin forming a broad semi- elliptical curve, sometimes nearly straight along the middle; dorsal margin concave in outline, so as to be nearly parallel with the base; false area rather well defined just behind the beaks, but becoming obsolete a little farther back; beaks nearly terminal, depressed, and incurred. Snrface of each valve ornamented by from sixteen to twenty- five small radiating costae, most of which pass from the beaks obliquely backward and downward to the posteito- basal margin, those near the anterior end being much more distant than the others, and separated by spaces from four to six times their own breadth. Small concentric wrinkles mark the surface in the other direction, giving the cost ® a slightly crennlated or subnodose appearance. Length, 1.60 inches: height ( at the beaks), 0.75 inch; breadth or convexity, 0.69 inch. In form, this species resembles somewhat varieties of Pholadomya foliacea, Agassiz ( Etud. Grit, sur les Moll., p. 102, pi. 7, particularly fig. 8), but its beaks are not near so oblique, and located farther back. Its cost ® are also smaller and more defined as well as more numerous, while its dorsal outline is more concave. Locality and position.- Nanaimo, Vancouver's Island, also on New • Castle Island; Cretaceous. Genus. GONIOMYA, Agassiz. GON10MYA BOBEALIS, Meek. Plate 2, fig. 2. Pholadomya ( Goniomya) borealis, Meek ( 1857), Trans. Albany lost., iv, 41. Shell transversely subovate or oblong- ovate, moderately compressed; anterior side rather abruptly rounded; posterior extremity truncated; cardinal margin sloping from the beaks, the anterior slope being more abrupt than the other; base forming a broad gentle curve, rounding up more gradually in front than behind; beaks moderately prominent, and located about half- way between the middle and the anterior end. Surface ornamented by from twenty to twenty- five small coatee, which pass down the sides of the shell from the dorsal margin behind and in front of the beaks, so as to meet at acute angles along an imaginary line extending from each beak obliquely backward and downward to near, the middle of the base. A few of those near the posterior and anterior ends reach the base before uniting to form an angle. Obscure lines of growth are also seen on portions of the surface. Length about 1.70 inches; height, 1.12 inches; breadth, 0.65 inch. The only specimen of this species in the collection is imperfect, being somewhat distorted by pressure, and broken at the extremities. The |
