a vascular pigmented membrane projecting into the vitreous humor within the globe of the eye in birds, and in many reptiles and fishes; -- also called marsupium.-the pubic bone.-any species of bivalve mollusks of the genus pecten, and numerous allied genera (family pectinidae); a scallop. see scallop.-the comb of a scorpion. see comb, 4 (b).