Report of the United States Geological Survey of the territories . rom the beaks to the posteriorbasal extremity, to which they impart a more or less angular outline; licemargins closed, and smooth within; beaks gibbous, very oblique, strongly 148 UNITED STATES GEOLOGICAL SURVEY OF THE TERRITORIES. incurved, and generally nearly anterior, or often overhanging the anteriormargin; lunule nearly always well defined; ligament rarely projecting above themargins of the escutcheon on each side; surface marked by concentric stria-,and often regular concentric ridges, which sometimes develop into stron
Report of the United States Geological Survey of the territories . rom the beaks to the posteriorbasal extremity, to which they impart a more or less angular outline; licemargins closed, and smooth within; beaks gibbous, very oblique, strongly 148 UNITED STATES GEOLOGICAL SURVEY OF THE TERRITORIES. incurved, and generally nearly anterior, or often overhanging the anteriormargin; lunule nearly always well defined; ligament rarely projecting above themargins of the escutcheon on each side; surface marked by concentric stria-,and often regular concentric ridges, which sometimes develop into strong,more or less projecting varices; hinge with three cardinal,* and one remoteposterior lateral teeth in each valve, the latter and the anterior tooth of theleft valve being cross-striate; muscular impressions distinct; pedal muscularscars disconnected from the upper ends of those of the anterior adductors;pallial line well defined, and generally a little straightened under the posteriormuscular impressions, but without any proper sinus. Fig. 9. Fiji. in. Fig. Veniella Conra&i, the type of Mortons genus. Fig. 1) sbows the exterior of the right valve of Mortons type-specimen, which is much fractured, butthe pieces have been fastened together, and the thawing made without regard to the fractures. Fig. 10 shows the hinge and interior of the same specimen. Fig. 11 drawn from a negative photograph of the last figure, and consequently shows the nature of thehinge and interior of the left valve of the same species, approximately. This group is made to include the following sections, which may pos-sibly be generically distinct: 1. veniella, Stoliczka (— Veniliu, Morton; not of Duponchel, or Alderand Hancock).Shell thin, or of moderate thickness, with posterior umbonalslopes prominent, angular, and imparting an angular outline to theposterior basal extremity ; surface with more or less strong, concen-tric ridges or varices; hinge nearly as in Cyprina, or with middletooth of left va
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Keywords: ., bookcentury1800, bookdecade1870, bookpublisherwashi, bookyear1876
