Definition of "cephalochordate" []

• Any of various primitive chordate animals of the subphylum Cephalochordata, such as the lancet, that lack a true vertebral column. (noun)
• Of, relating to, or belonging to the subphylum Cephalochordata. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "In the middle is a cephalochordate, Amphioxus, also a filter feeder, but capable of free swimming."
• "In the invertebrate cephalochordate Amphioxus, there is a family of very immunoglobulin like-molecules, Variable domain Chitin Binding Proteins, which are involved in innate immunity."
• "In summary, the cephalochordate affinity of Pikaia is at best only weakly indicated by the characters visible in fossils discovered so far."