[L. ephippium horse-cloth, saddle, ad. Gr. ἐφίππιος adj. ‘that is for putting on a horse,’ f. ἐπί upon + ἴππος horse.]
1. Anat. A saddle-shaped depression of the sphenoid bone.
1842. Dunglison, Medical Lex., s.v.
2. Zool. The envelope enclosing the winter ova of the Daphniidæ (a genus of the Crustaceans), which is situated between the back of the animal and the carapace, and probably is a development from the latter. It is shed with the carapace.
1841–71. T. R. Jones, Anim. Kingd. (ed. 4), 455. As winter approaches, however, the Daphnia may be seen with a dark opaque substance within the back of the shell, which has been called the ephippium, from its resemblance to a saddle…. The ephippium is really only an altered part of the carapace.
1877. Huxley, Anat. Inv. Anim., vi. 287. The ephippium sinks to the bottom, and, sooner or later, its contents give rise to young Daphniæ.
