from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of various primitive chordate animals of the subphylum Cephalochordata, such as the lancet, that lack a true vertebral column.
- adj. Of, relating to, or belonging to the subphylum Cephalochordata.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any of the primitive fishlike creatures, of the subphylum Cephalochordata, including the lancets, that lack a true spine but have a notochord which, in the case of cephalochordates, reaches into the head, contrary to the Urochordata
- adj. Of or pertaining to these creatures.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. fish-like animals having a notochord rather than a true spinal column
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.
FGFRL1, the gene for the fifth member of the fibroblast growth factor receptor (FGFR) family, is found in all vertebrates from fish to man and in the cephalochordate amphioxus.
ther diminishes the credibility of the cephalochordate—echinoderm link