Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for proctodaeum
Renal caecal tubes (Malpighian tubes) open into the proctodaeum.
Renal excretory caeca (Malpighian tubes) are developed from the proctodaeum (not from mesenteron as in scorpion and Amphipoda).
The third or outermost chamber, the proctodaeum, is closed externally by the sphincter ani; the orifice is quite circular.