acraniateadj.n.

1876 Canad. Jrnl. Oct. 243 This..stage may be called provertebratum, of which the only acraniate vertebrate living, ‘amphioxus’, is the nearest representative.

1879 A. S. Packard Zool. viii. 401 The Vertebrates are divided into the skulless [sic] or acraniate..and the skulled or craniate (Craniata).

1894 A. Willey Amphioxus & Ancestry of Vertebr. ii. 46 Amphioxus, while possessing the general facies of a fish..has no skull, or, in other words..is Acraniate.

1947 Q. Rev. Biol. 22 120 Neither the endostyle of the tunicate Perophora annectens..nor that of the acraniate Amphioxus..is capable of storing radioactive iodine.

1998 L. Margulis & K. V. Schwartz Five Kingdoms (ed. 3) iii. 322/1 Acraniate chordates—tunicates and cephalochordates (Phylum A-36)—are considered by some to be subphyla within Phylum Chordata.

1886 Amer. Naturalist 20 181 Diagrams..represent..respectively the brain of an acraniate, a marsipobranch, an elasmobranch and a mammal.

1893 Stud. Biol. Lab. Johns Hopkins Univ. 5 213 (title) An undescribed acraniate: asymmetron lucayanum.

1946 Physiol. Zool. 19 373 The endostyle of ammocoetes is definitely not analogous with the endostylar apparatus of acraniates.

1977 Compar. Biochem. & Physiol. B. 57 167/1 The phylogenetic interrelationships between the three chordate subphyla, namely the tunicates, the acraniates, and the vertebrates, are still quite obscure.

1987 Gen. & Compar. Endocrinol. 66 40 Of the four groups of chordates, tunicates,..appendicularians, acraniates, and craniates, the first three groups are suspension feeders.

1997 G. S. Helfman et al. Diversity of Fishes xiii. 197/2 Lancelets are intriguing in their lack of many typical chordate structures. They differ from conventional fishes by lacking most parts of a head (e.g., no cranium, brain, eyes, external nostrils, or ears); hence they are sometimes called acraniates.