The Collaborative International Dictionary of English v.0.48:

Gonangium \Go`nan*gi"um\, n.; pl. L. Gonangia, E.
   Gonangiums. [NL., fr. Gr. ? offspring + ? vessel.] (Zool.)
   See Gonotheca.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Gonotheca \Gon`o*the"ca\, n.; pl. Gonothec?. [NL., fr. Gr. ?
   offspring + ? box.] (Zool.)
   A capsule developed on certain hydroids (Thecaphora),
   inclosing the blastostyle upon which the medusoid buds or
   gonophores are developed; -- called also gonangium, and
   teleophore. See Hydroidea, and Illust. of
   Campanularian.
   [1913 Webster]