. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . specimens between 18,8 mm and 38,58mm were cleared and stained (Hollister 1934) so that fin movements atmetamorphosis in S. ocellata could be compared with the changes described forother species during this stage of development. Measurements of head length, eye diameter, snout length, body depth(at the base of the pectoral fin) and lengths to dorsal, anal and pelvic fins wererelated to standard length. In considering metamorphosis of the larvae it wasfound that measurements from snout to dorsal and anal fi
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . specimens between 18,8 mm and 38,58mm were cleared and stained (Hollister 1934) so that fin movements atmetamorphosis in S. ocellata could be compared with the changes described forother species during this stage of development. Measurements of head length, eye diameter, snout length, body depth(at the base of the pectoral fin) and lengths to dorsal, anal and pelvic fins wererelated to standard length. In considering metamorphosis of the larvae it wasfound that measurements from snout to dorsal and anal fins (as used by Lebour1921 and Baker 1972) did not reflect clearly the changes in fin positionevident in myotome (and vertebral) counts. This was found to be attributableto the increased rate of head growth and therefore measurements between thecleithrum and dorsal fin and cleithrum and anal fin were used instead. Themeasurements in the figures refer to standard length. 128 ANNALS OF THE SOUTH AFRICAN MUSEUM 18 20 22 24 Cape Frio Rocky Point SOUTH WEST AFRICA Palgrave Point. • .vCape Cross Walvis Bay Hollams Bird Is 12 16 Fig. 1. Map of South West African coast, showing the grid (small dots) of the SWAPELSprogramme. Large dots indicate stations at which Sardinops ocellata larvae were obtained. LARVAL DEVELOPMENT OF SARDINOPS OCELLATA 129 GENERAL DESCRIPTION Sardinops ocellata larvae pass through three stages of development afterhatching and before attaining the juvenile stage. These stages are the yolk-sacstage which may be regarded as a continuation of embryonic developmentsubsequent to hatching; the larval stage; and the metamorphic stage when thelarvae undergo changes and begin to acquire characteristics of the adult. Thejuvenile stage is that in which the fish possess all the basic adult characteristics. YOLK-SAC STAGE LARVAE (FigS 2-3) The newly hatched larvae of S. ocellata are 2,75-2,95 mm in length. Thehead, with unpigmented eyes and undeveloped mouth, is flexed downwa
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