. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. llemova remora. Segments of disc from above (A) and below (B). /, fin-ray ; r, radial ; b, basal. The small lateral expansions of the radials seen in most Percoids have become large overlapping laminae in the Echeneididse; the basalia are nearly normal, except that they are directed very obliquely backwards. It is difficult to imagine the initial stages of this extra- ordinary modification, but it seems not impossible that some pelagic Percoid with the habit of associating wit
. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. llemova remora. Segments of disc from above (A) and below (B). /, fin-ray ; r, radial ; b, basal. The small lateral expansions of the radials seen in most Percoids have become large overlapping laminae in the Echeneididse; the basalia are nearly normal, except that they are directed very obliquely backwards. It is difficult to imagine the initial stages of this extra- ordinary modification, but it seems not impossible that some pelagic Percoid with the habit of associating with sharks, like the pilot-fish (Naucrates), should have found that the spinous dorsal fin, when depressed in its groove, could be used more or less effectively as an adhesive organ, and should have acquii^ed the habit, when swimming close to its protector, of fastening on. The other fins are very similar to those of the Pomatomidie, Carangidse, Rhachiceutridse, &c,, in structure and position, and the Discocephali may well have evolved from Percoids of this type. The most important characters of the Discocephali, in addition to the peculiar structure of the dorsal fin, are the following:— Mouth not protractile, with the slender maxillary firmly adherent to the pnemaxillary ; dentary attached to articulare. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original London, Taylor and Francis, Ltd
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Keywords: ., bookce, booksubjectbotany, booksubjectgeology, booksubjectzoology
