ctenocyst

From cteno- +‎ cyst, in which the first component can be understood as a clipping of ctenophore or of the taxonomic name Ctenophora.

ctenocyst (plural ctenocysts)

1. (archaic, zoology) A sensory organ of the ctenophores (comb jellies). It is a black speck in the depression on the aboral side of the body.

In modern literature, it is normally referred to as the aboral sense organ, or aboral organ (AO)

• “ctenocyst”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.