This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1894 edition. Excerpt: .Siphonotreta, de Verneuil. 1845.

(Plate 4, Figs. 22-26.) Shell elongate-oval. inequivalve; valves unarticulated. Pediclevalve the more convex, witha straight, elevated, conical, and perforated beak, the circular foramen opening at the apex and communicating with the interior of the shell by a tubular canal, which narrows slightly as it passes inward. N o cardinal area or deltidium is present, the growth-lines passing between the beak and the posterior margin as elsewhere on the shell. Brachial valve depressed-convex; beak marginal; posterior margin regularly arched and thickened. Interior of pedicle-valve with muscular impressions confined to the umbonal region.

Adjacent to the opening of the sipho, and just within the cardinal margin lie two elongate scars which are accompanied on either side by broader, somewhat expanded or flnbellate, simple and less distinct impressions. Directly in front of the middle pair and in the axis of the shell lies a small central scar, and at either side of it a transversely elongate impression-. These latter impressions are distinctly separated from the former by a transverse ridge. In the brachial valve the impressions are equally concentrated, the entire muscular area being bounded on its posterior margin by a prominent ridge which, at the sides, merges into a compound lateral scar. The central portion of the area is much depressed and is divided axially by a narrow ridge or septum. ' Shell ornamented with concentric lines and ridges, the epidermal layer bearing hollow spines, which are distended at the base. Shell-substance calcareo-corneous, the layers beneath the epidermis being punctured by radiating and branching tubules. These layers are concentric and not parallel to the internal surface.

Type, .