FISHERY BULLETIN: VOL. 76, NO. 1 



y 



20b 



20c 



Figure 19. — Colonies of Zoothamnium sp. attached to end of gill filaments in pink shrimp; this represents a light infestation; 

 heavy infections would cover all filaments. x200. 



Figure 20. — a. Phase contrast photomicrograph of Zoothamnium colony showing stalk myonemes (M) that are continuous 

 with one another, the major distinguishing characteristic of the genus; note inverted bell shape of contracted trophonts (T) and 

 thickness of stalk sheath that surround myonemes (arrow). x500. b. Protargol treated specimens of Zoothamnium; note 

 beltlike, horseshoe-shaped macronucleus and Protargol -positive myonemes of stalk (arrow). xl,200. c. Protargol-treated 

 Zoothamnium; trophont ( in focus) shows peniculus (P) in infundibulum ( arrow); note pattern of kineties (K) making up peniculus. 

 X 1,200. 



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