Pecten maximus. P. medius. P. Jacobæus. P. bifrons. P. ziczac. P. Latirentii. P. rastellum. P. turgidus. P. flagellatus. P. aspersus. P. flavidulus. P. plica. P. pleuronectes. P. obliteratus. P. Japonicus. P. Magellanicus. P. purpuratus. P. lineolaris. P. radula. P. nodosus. P. pallium. P. pes-felis. P. tigris. P. imbricatus. P. histrionicus. P. sauciatus. P. opercularis. P. asperrimus. P. senatorius. P. aurantius. P. florens. P. varius. P. sanguineus. P. sinuosus. P. ornatus. P. glaber. P. sulcatus. P. virgo. P. unicolor. P. griseus. P. distans. P. Isabella. P. lineatus. P. flabellatus. P. irradians. P. flexuosa. P. dispar. P. quadriradiatus. P. Islandicus. P. inflexus. P. pellucidus. P. Tranquebaricus. P. gibbus. P. miniaceus. P. pusio. P. hybridus. P. sulphureus. P. lividus. _P. glaber._ The glabrous Scallop. Pl. 15, fig. 4. Species of which the two valves are ribbed and almost equally convex, the right a little less, and having its inferior ear less broad than the left, so as to produce a kind of groove for the passage of the byssus. _P. Jacobæus._ The scallop of St. James. Species very inequivalve; the left valve being very flat, the right convex; ears equal. _P. pleuronectes._ The sole Scallop. Species equivalve, not closing; surface smooth and ribbed within; one valve perfectly white, the other of a brownish or reddish colour. 4. Plagiostoma. Ten fossil species.