acrania
A*cra"ni*a, n. Etym: [NL., from Gr. 1. (Physiol.) Defn: Partial or total absence of the skull. 2. pl. (Zoöl.) Defn: The lowest group of Vertebrata, including the amphioxus, in which no skull exists.
A*cra"ni*a, n. Etym: [NL., from Gr. 1. (Physiol.) Defn: Partial or total absence of the skull. 2. pl. (Zoöl.) Defn: The lowest group of Vertebrata, including the amphioxus, in which no skull exists.