FISHERY BULLETIN: VOL. 76, NO. 1 



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Figure 13. — Nosema nelsoni spores in fresh squash preparation of muscle from pink shrimp, x 1,500. 



Figure 14. — White or cotton appearance of organs and muscle of penaeid shrimp infected \N\ih. Nosema nelsoni, and Thelohania 

 penaei; note opaque white appearance of gonads (arrow). 



Figure 15. — a. Abdominal musculature heavily infected with Nosema nelsoni; note long spore masses between and around every 

 muscle bundle (arrows). xlOO. b. Higher magnification of spore masses of A^osema in histological section of muscle. x500. 



(1971), Thelohania hunterae (a nomen nudum) 

 was probably T. duorara. 



Roth and Iversen (1971) reported attempts to 

 transmit T. duorara to uninfected pink shrimp in 

 the laboratory. They were unable to do this with 

 their method of feeding heavily infected tissue. 

 These authors did supply some clues as to the 

 possible modes of transmission in nature. They 

 observed that spores of T. duorara found between 

 old cuticle and new cuticle at time of molting could 

 infect shrimp that feed on cast cuticles. Therefore, 



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transmission could depend only on molting of the 

 exoskeleton and not on death of the infected host. 

 Iversen and Kelly ( 1976) have reported concur- 

 rent infections of T. duorara and T. penaei in 

 single specimens of pink shrimp. 



Pleistophora ( = Plhtophora) penaei 

 Constransitch 1970 



Members of this genus are characterized by 

 sporocysts that contain 16 or more spores. Kruse 



