GROUPS OF NONVERTEBRATE CHORDATES

There are two major groups of nonvertebrate chordates: tunicates and lancelets (sometimes called amphioxus).

CEPHALOCHORDATA: Lancelets

Lancelets are fishlike animals that have bilateral symmetry and live in salt water. They are filter feeders and have no internal skeleton. Example: Branchiostoma

Two lancelets pokes the sand.

Two lancelets, Branchiostoma lanceolatum, poking out of sand.

UROCHORDATA: Tunicates

Tunicates are filter feeders that live in salt water. Most adults have a tough outer covering (“tunic”) and no body symmetry; most display chordate features and bilateral symmetry only during larval stages. Many adults are stationary; some are free-swimming. Examples: sea squirts, sea peaches, salps

Pastel sea squirts.

Pastel Sea Squirt

Sea squirts

Sea Squirts


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Table of Contents

Miller & Levine Biology UNIT 1 The Nature of Life UNIT 2 Ecology UNIT 3 Cells UNIT 4 Genetics UNIT 5 Evolution UNIT 6 From Microorganisms to Plants UNIT 7 Animals UNIT 8 The Human Body A Visual Guide to The Diversity of Life Appendices Glossary Index Credits