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UNITED STATES NATIONAL IVIUSEUM BULLETIN 251 



Figure 59. — Botryllus tuheratus Ritter & Forsyth: a, colony from Amoy; b, arrangement 

 of contracted zooids In a specimen from China; c, 0.5 mm. long young zooid from the 

 Palau Islands colony; d, inside of prebranchial area of same zooid, showing two tentacles, 

 enlarged. 



Test soft, gelatinous, translucent to transparent, and may be yellow- 

 ish white or faintly purplish brown. Zooids always pigmented in 

 dark purplish brown and arranged regularly in stellate systems ; each 

 system consists of 4-12 zooids, most frequently 7-10. Colony surface 

 usually exposed, although sometimes it carries some mud. Specimens 

 from Palau Islands and Chinese waters seem to be in budding stages, 

 with darkly pigmented old zooids arranged in stellate systems and all 

 contracted strongly; newly formed young zooids colorless or very 

 lightly pigmented, wholly expanded, situated one at ventral side of 

 each old zooid, filling interspace between systems formed by old zooids, 

 but without forming any systems by themselves and sometimes open- 

 ing to exterior individually. In the colonies from Chinese waters, 

 all zooids have lost communication with the exterior and have buried 

 themselves completely in test. Large old and young small zooids 

 arranged roughly in stellate systems as shown in figure h; probably 

 a stage just before reformation of stellate systems by both old and 

 young zooids. Zooids situated obliquely. Stigmatal rows 4, stig- 

 mata 11-19 in a row and arranged (D= dorsal, V= ventral) : D 4-6 



