. Chordate morphology. Morphology (Animals); Chordata. MODIFIED HOMOCERCAL FIERASPIS GEPHYROCERCAL Figure 6-42. Evolution of toil fins in fishes. of the originally heterocercal tail; this is also an abbrevi- ated homocercal type. In the dipnoans the tail ranges from that of the living lungfishes, a protocercal type (prolos—first, primary) in which the ray-supported part of the fin is limited to the margins, back in time to the heterocercal tail of Dipterus or the protocercal tail of Phaneropleuron, which has a separate anal, or Uronemus. Among crossopterygians there are those which are diphyce

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. Chordate morphology. Morphology (Animals); Chordata. MODIFIED HOMOCERCAL FIERASPIS GEPHYROCERCAL Figure 6-42. Evolution of toil fins in fishes. of the originally heterocercal tail; this is also an abbrevi- ated homocercal type. In the dipnoans the tail ranges from that of the living lungfishes, a protocercal type (prolos—first, primary) in which the ray-supported part of the fin is limited to the margins, back in time to the heterocercal tail of Dipterus or the protocercal tail of Phaneropleuron, which has a separate anal, or Uronemus. Among crossopterygians there are those which are diphycercal {diphyes—double) or modified diphy- cercal (Eusthenopteron), but most are heterocercal. Actinis- MEDIAN FINS 169. 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 Jollie, Malcolm. New York, Reinhold

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