FAMILY XVIII.
Pectinea. Seven genera.
1. Genus Pedum. Pl. [IX].
Animal. Unknown, but probably byssiferous.
Shell. Subtriangular, inequilateral, inequivalve, with rounded summits, freely marked, unequal and distant: the right valve inflated, widened at its inferior and posterior edge, sloped anteriorly, and subauriculated, the left not being so; hinge toothless, anterior or buccal; ligament inserted in an oblique cavity prolonged outwardly to the summits, and carried within into a spoon-like cavity. Inhabits the Indian Ocean. One species.
- Pedum spondyloideum.
2. Genus Lima. Pl. [IX].
Animal. Body moderately compressed; a byssiferous abdominal appendage; edges of the mantle furnished with tentacular cirri in several rows; mouth surrounded with a very thick fringed lip.
Shell. Oval, more or less oblique, nearly equivalve, subauriculated, regularly gaping at the anterior portion of the inferior edge; summits anterior and distant; hinge buccal, longitudinal, toothless; ligament rounded, nearly exterior, inserted in an excavation in each valve; a central muscular impression, divided into three very distinct parts. Inhabits the Indian, Australasian, American, and Mediterranean seas. Six living species. Eleven fossil.
- Lima inflata.
- L. squamosa.
- L. annulata.
- L. glacialis.
- L. fragilis.
- L. linguatula.