polygyrate

polygyrate

1. (malacology) Multiply gyrate, like the protoconches of various Gemmula ammonites. ?
   • 1953, Auckland Institute and Museum, Bulletin of the Auckland Institute and Museum:

     [...] polygyrate diagonally cancellated protoconch, but in that genus the adult whorls are pagodiform, strongly keeled […] polygyrate to paucispiral and almost smooth, and the reversed L-sinus is sometimes rendered U-shaped to subtubular, when restricted above by a parietal tubercle. The Daphnellids are very numerous in both genera and species […]

   • 1967, J. C. W. Cope, The Palaeontology and Stratigraphy of the Lower Part of the Upper Kimmeridge Clay of Dorset:

     [...] gyrate furcation, and often a tendency to become fasciculate or virgatotome; secondary ribs obsolescent in some [...] polygyrate ribs and intercalatory secondaries. Microconchs 100-112 mm. in diameter with following rib densities […]

   • 1977, Acta geologica polonica:

     ... polygyrate or bidichotomous to fasciculate (rarely virgatotome) ribs, more loosely spaced and coarser. External whorls of macroconch forms with dichotomous to polygyrate ribs […]