m 
CONCHIFERA. 
Genus 12.—VULSELLA.— Lamarck. 
Generic Character. —Longitudinal, subequivalve, irregular, 
and free ; umbones equal; hinge, with a projecting callosity de¬ 
pressed above, and a conical oblique hollow for the ligament. 
Vulsella lingulata. — The Latchet Vulsella. 
Plate LXXXVII. fig. 4. 
Elongated, depressed, transversely striated; pale yellowish 
brown, with longitudinal darker stripes. Four inches long. 
Inhabits the Indian ocean. 
Genus 13.—OSTREA.— Linnaeus. 
Generic Character. —Shell adhering to extraneous bodies; iu- 
equivalve and irregular, with the beaks separated, and the up¬ 
per valve advanced as the animal enlarges ; hinge without teeth; 
the lower valve largest; and concave ligament semi-internal; the 
hollow of attachment increasing with age. 
This genus has two sections, * with a simple waved margin, 
and not plicated, ** margins plicated. 
Ostrea edulis. — The Edible Ostrea, or Oyster. 
Plate LXXXVIII. fig. 3. 
Sub-orbicular, rugged, with undulated, imbricated scales, and 
transversely striated; one valve flat, and the other convex; 
outside brownish-green ; inside pearly-white ; exceedingly varia¬ 
ble in size. Inhabits the coasts of Europe. 
Genus 14.— GRYPHJEA.— Lamarck. 
Generic Character. —Inequivalve, free; lower valve largest 
and concave ; beaks large, projecting, and spirally twisted ; up¬ 
per valve small, flat, and acting as a lid; hinge without teeth; 
the cardinal hollows oblong, arcuated; having one muscular im¬ 
pression. Animal unknown. 
Gryphcea angulata, — The Angulated Gryph^ea. 
Plate LXXXVIII. fig. 1. 
Oblong-ovate, with three longitudinal, carinated ribs below; 
beak large, somewhat oblique. Four inches long. Habitation 
unknown. A specimen of this rare shell is in the Museum of 
the Jardin du Roi, at Paris. 
