Acephalous

also, acephalic
[ey-suh-fal-ik] /ˌeɪ səˈfæl ɪk/ (show ipa). zoology. headless; lacking a distinct head.
without a leader or ruler.
historical examples

he found it more ‘acephalous’ than ever; ‘less order; less unity of purpose.’
the life of william ewart gladstone, vol. 1 (of 3) john morley

such is a summary description of all the acephalous molluscs.
the ocean world: louis figuier

i cannot imagine anything more manifestly made to be a tyranny than such an acephalous aristocracy.
what i saw in america g. k. chesterton

but in its present acephalous condition it is but a fragment of sciencea headless corpse, unfit to rank among complete sciences.
buchanan’s journal of man, april 1887 various

anarchism, with its knife and bomb, is a miscarriage of socialism, an acephalous birth from that fruitful mother.
new worlds for old herbert george wells

its cercari are usually found in an acephalous mollusc, known by the name of cyclas cornea.
animal parasites and messmates p. j. van beneden

almost all bivalve sh-lls, or those of acephalous mollusca, are marine, about ten only out of ninety genera being freshwater.
a manual of elementary geology charles lyell.

adjective
having no head or one that is reduced and indistinct, as certain insect larvae
having or recognizing no ruler or leader
adj.

“headless,” 1731, from french acéphale + -ous, or directly from late latin acephalus, from greek akephalos, from a- “not” + kephale “head” (see cephalo-).