fish, in zoology: The Jawless Fishes

These primitive fishes lack jaws and the paired pelvic and pectoral fins characteristic of more advanced fishes. The two living types are the bloodsucking lampreys and the scavenging hagfishes. Fishes of the extinct class Placodermi, the armored fishes, were the first vertebrates to develop jaws and paired fins. These fish had bony skeletons and were covered with bony armor.

Sections in this article:

• Introduction
• The Bony Fishes
• The Cartilaginous Fishes
• The Jawless Fishes
• Reproduction
• Characteristic Anatomical Features
• Bibliography

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2024, Columbia University Press. All rights reserved.

See more Encyclopedia articles on: Vertebrate Zoology