. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . to a more marked degree (Fig. 7). In addition to this overall increase in bodydepth in larvae of more than 22 mm , it may be seen from Figure 4C thatthe myotomes at this stage start to grow ventrally so that they begin to coverthe gut. At 23 mm the myotomes merely obscure the dorsal edge of the gut,but their expansion becomes more marked, first over the anterior half of thegut and later extending also over the posterior half of the gut, so that by 29,5 the gut is almost entirely covered by myotome ti
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . to a more marked degree (Fig. 7). In addition to this overall increase in bodydepth in larvae of more than 22 mm , it may be seen from Figure 4C thatthe myotomes at this stage start to grow ventrally so that they begin to coverthe gut. At 23 mm the myotomes merely obscure the dorsal edge of the gut,but their expansion becomes more marked, first over the anterior half of thegut and later extending also over the posterior half of the gut, so that by 29,5 the gut is almost entirely covered by myotome tissue, except for a smallarea close to the anus. At this stage, however, they have not yet fused larvae of 30-31 mm most myotomes anterior to the pelvic fins are fusedmid-ventrally and the first two or three scutes have developed in the mostanterior mid-ventral region. In common with the development of other clupeids, one of the mostmarked features of metamorphosis in S. ocellata is the alteration in the position LARVAL DEVELOPMENT OF SARDINOPS OCELLATA 137. > O3 +3 pq _ B O .2 °33 o O +j a c Hh 138 ANNALS OF THE SOUTH AFRICAN MUSEUM of the dorsal and anal fins which occurs during this stage. Instead of the steadyrate of increase shown in the distances from cleithrum to dorsal fin and cleithrumto anal fin (Figs 8-9) during the larval stage, metamorphic stage larvae show aslight decrease in cleithrum to dorsal fin distance and only a very slight con-tinued increase in cleithrum to anal fin distance. These changes in the patternof growth occur in larvae of 24-33 mm They can be attributed to the anteriormigration of the dorsal and anal fins, relative to myotomes and vertebrae. Mostauthors (Lebour 1921; Ford 1930; Ahlstrom 1943, 1968) documented finmigration relative to vertebrae, but others (Schnakenbeck 1929; Baker 1972)used myotomes. Attempts to stain vertebrae in specimens 18-20 mm werenot satisfactory as the most anterior vertebrae did not take u
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
