Studies on the Chromosomes of the ScallopPecten Maximus(L.) and Related Species

A number of species of the family Pectinidae (Lamellibranchia, Mollusca) are of considerable commercial importance in many parts of the world. Many of these are being reared in laboratories and hatcheries and this has made easier studies of cytogenetics using eggs and embryos, and ultimately will make studies of their genetics feasible. Recently, simple squash techniques have provided a fast and reliable method for obtaining chromosome numbers from eggs and embryos of several bivalves includingMercenariaspp. (Menzel & Menzel, 1965),Ostrea luridaandCrassostera gigas(Ahmed & Sparks, 1967),Mytilusspp. (Ahmed & Sparks, 1970), andCrassostreaspp. (Menzel, 1968). In 1967, Longwell, Stiles & Smith published the karyotype ofCrassostrea virginicaobtained from embryos which had been treated with colchicine.