I. Rays and Skates of Devon and Cornwall. Methods of Rapid Identification on the Fishmarket • II. Idem. A Study of the Fishery, with Notes on the Occurrence, Migrations and Habits of the Species • III. Idem. The Proportions of the Sexes in Nature and in Commercial Landings and their Significance to the Fishery • IV. Growth of Claspers and Cloaca in Raia clavata L. • V. Migrations and Growth of the Thornback Ray, Raia clavata L. • VI. Reprinted front the Journal of the Marine Biological Association of the United Kingdom, Vol. xxvii, November 1948, pages 517 -539 CONTRIBUTIONS TO THE BIOLOGY OF THE MACKEREL, SCOMBER SCOMBRUS L.: MACKEREL MIGRATIONS IN THE ENGLISH CHANNEL AND CELTIC SEA. By G. A. Steven • VII. Reprinted from the Journal of the Marine Biological Association of the United Kingdom, Vol. xxviii, December 1949, pages 555 -581 I.CONTRIBUTIONS TO THE BIOLOGY OF THE MACKEREL SCOMBER SCOMBRUS L. II. A STUDY OF THE FISHERY IN THE SOUTHWEST OF ENGLAND, WITH SPECIAL REFERENCE TO SPAWNING, FEEDING, AND `FISHERMEN'S SIGNS'. By G. A. Steven • VIII. Reprinted from the ,journal of the Marine Biological Association of the United Kingdom, Vol. xxx, February 1952, pages 549 -568 CONTRIBUTIONS TO THE BIOLOGY OF THE MACKEREL, SCOMBER SCOMBRUS L. III. AGE AND GROWTH By G. A. Steven