Zool. [mod.L., dim. of L. spīra SPIRE sb.3] A genus of cephalopods having a flat spiral shell in the hinder part of the body; an animal of this genus, or one of the shells.
1835–6. Todd’s Cycl. Anat., I. 546/2. The shell of the Spirula is … convoluted on one plane, with the whorls disjoined.
1851. Woodward, Mollusca, I. 13. The argonaut, with his relative the spirula, both carnivorous.
1881. Cassell’s Nat. Hist., V. 181. The beautiful pearly-white shell known as Spirula.
So Spirule. [Cf. F. spirule.]
1851. Mary Roberts, Mollusca, 57. The Spirule, like the Nautilus, has a chambered, siphonated shell.
