. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. Figure 30. Scales of Peprilus snyderi: region. From mm SL specimen. = scale from trunk below lateral line; b = lateral line scale from mid-trunk regressed, age-dependent swimbladders is being initiated. Character associations. Listed in Table 21 are the mean values of some morpho- metric and meristic characters which illus- trate trends in sets of characters among the species of Peprilus. P. para, the short- est, deepest-bodied species, is listed first in the table, followed in order bv the more elongate species
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. Figure 30. Scales of Peprilus snyderi: region. From mm SL specimen. = scale from trunk below lateral line; b = lateral line scale from mid-trunk regressed, age-dependent swimbladders is being initiated. Character associations. Listed in Table 21 are the mean values of some morpho- metric and meristic characters which illus- trate trends in sets of characters among the species of Peprilus. P. para, the short- est, deepest-bodied species, is listed first in the table, followed in order bv the more elongate species. From this ranking the table shows how other characters relate to that of body depth. Greatest body depth is associated with the greatest preanal and predorsal distances, the longest pectoral, the largest eye, and the fewest vertebrae. In the most elongate species, P. snyderi, these character values are largely reversed. P. snyderi probably does not have the quick-turning ability attained by P. paru or P. ovatus, for example. I have not analyzed unit characters or their roles by the techniques of Olson (1964), although this approach might be instructive, especially if applied to the entire suborder. Skin and scales. The skin of Peprilus is thin and, as in most other stromateoid fishes, the scales (Fig. 30) are thin, cycloid, irregular in shape, highly deciduous, and in shallow pockets in the skin. The lateral line scales (Fig. 30b) have a simple tube passing through the middle, and are less deciduous than scales of other parts of the body. The scale condition in Peprilus may be important in achieving greater maneu- verability and may represent a stage in a trend toward complete loss of scales. The cephalic lateral line consists of pores and branching canals on the cheek, opercular area, snout, lower jaw, and top of head. In the stromateoid fishes there is usually a well-developed subdermal canal system which communicates to the surface through small pores scattered over the he
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