acephalous

• […] Mr. Cruickshank saw a Monster nine Months old, which lived thirty-six Hours after it was born, though it had no Cranium: […] But is this a Reason that we should believe the vital Functions and the Increase of the Body have no dependence on the Brain? I think not: for such acephalous Subjects never live long […]1792, Walter Vaughan, An Essay, Philosophical and Medical, Concerning Modern Clothing, Rochester, pages 58–59:
• “But tell me, my Dea—my Psyche!— (With your wings outspread as to race With that swift and acephalous Nike Who lost her bean somewhere in Thrace)—1916, Don Marquis, “The Little Group Gives a Pagan Masque”, in Hermione and Her Little Group of Serious Thinkers, New York: Appleton, page 164:

Applied to bivalve mollusks

• an acephalous society / community
• […] an Oecumenical Council is a whole, and a Body whereof the Pope, or he that presides in it in his place, is the Head[.] For there is no Acephalous Council, as M. Schelstrate speaks, that is to say, without a Head, calling that of Constance so in the Absence of the Pope.1685, Louis Maimbourg, chapter 25, in Archibald Lovell, transl., An Historical Treatise of the Foundation and Prerogatives of the Church of Rome and of Her Bishops, London: Jos. Hindmarsh, pages 318–319:

• They have acephalous or headless Verses, which commence with a short Syllable instead of a long one:1746, Claude Lancelot, translated by T. Nugent, A New Method of Learning with Greater Facility the Greek Tongue, London: J. Nourse and G. Hawkins, Volume 2, Book 9, p. 348:
• Sometimes verse lines “jump” the first syllable (in anapaestic and dactylic measures the first two syllables) of a regular metre. Such lines are said to be acephalous (headless) or, as acrostic writers would put it, “beheaded.”1934, Robert Swann, Frank Sidgwick, chapter 2, in The Making of Verse: A Guide to English Metres, London: Sidgwick & Jackson, page 16:

• 1828, Thomas de Quincey, review of Elements of Rhetoric by Richard Whately, in Blackwood’s Edinburgh Magazine, Volume 24, No. 147, December 1828, p. 905, Men wrote eloquently, because they wrote feelingly: they wrote idiomatically, because they wrote naturally, and without affectation: but if a false or acephalous structure of sentence,—if a barbarous idiom—or an exotic word happened to present itself, no writer of the 17th century seems to have had any such scrupulous sense of the dignity belonging to his own language, as should make it a duty to reject it, or worth his while to re-model a line.