Acoela (Acoelomorpha) from the northern beaches of the state of São Paulo, Brazil, and a systematic revision of the family Otocelididae Author Hooge, Matthew D. Author Rocha, Carlos E. F. text Zootaxa 2006 1335 1 50 journal article 10.5281/zenodo.174287 26ac73b9-1c53-4f82-bc02-78a055ba31e9 1175-5326 174287 Haplocelis dichona ( Marcus, 1954 ) ( Fig. 24 ) Otocelis dichona : Marcus 1954 (p 429). Haplocelis dichone : Dörjes 1968 (p 102). Haplocelis dichona : Dörjes and Karling 1975 (p 180); Ehlers and Dörjes 1979 (p 34). Material . MZUSP PL . 192, one set of 1.5-µm-thick serial sagittal sections of epoxyembedded specimen stained with toluidine blue; living specimens in squeeze preparation; whole mounts for fluorescence imaging of musculature. Locality . Praia São Francisco, São Sebastião, São Paulo, Brazil , from intertidal coarse sand ( 23°45’45.1”S , 45°24’27.1”W ). Description . Living specimens ~ 950 m long and ~ 250 m wide ( Fig. 24 A). Body without coloration in transmitted light. Rhabdoids scattered across body. Mouth opening on ventral surface, middle of body. Ovaries and testes paired. Common gonopore terminal at posterior end; opens dorsally to vagina and ventrally to male copulatory organ. Vagina leads to bursa with one or two winding bursal nozzles ( Fig. 24 B). Long, coiled, muscular, glandular penis invaginated into muscular seminal vesicle containing sperm ( Fig. 24 B). Remarks . This species can be distinguished from all other species of acoels by its winding curlicue bursal nozzle and penis. Marcus (1954) described his specimens of H. dichona , collected from Ilhabela, as having two bursal nozzles; however, all of our specimens possessed only a single nozzle.