It is still more remarkable than the amphioxus or lancelet, which has been long known.
This shows that amphioxus is a comparatively primitive type.
In Embryology an attempt has been made to compare the origin of the cœlom in amphioxus and in Balanoglossus.
I remarked that his friend next door had shown me an amphioxus.
Diagrammatic sections of amphioxus in its early stages (founded upon Kowalevsky's observations).
Wilson, separation of segmentation spheres of amphioxus egg, 60.
The egg of the lowest vertebrate, amphioxus, shows these changes in a simple and apparently primitive form.
They form the rudiment of the notochord, which, as in amphioxus, is derived from the dorsal wall of the archenteron.
Conklin has established the existence of a definite structure in the unfertilized eggs of Ascidians, amphioxus, and many molluscs.
This cavity is the segmentation cavity equivalent to that present in amphioxus, Amphibia, etc.