trionychoidea

from The Century Dictionary.

• The Trionychidæ regarded as a suborder of Chelonia, of equal rank with Athecæ (the Sphargididæ) and with Testudinata, 2, or Thecophora (all other chelonians).

from the GNU version of the Collaborative International Dictionary of English.

• noun plural (Zoöl.) A division of chelonians which comprises Trionyx and allied genera; -- called also Trionychoides, and Trionychina.