Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . consisting of fine sand particles (Fig. 9A). Rectalcaecum small, spherical. Anal vesicles. Anal vesicles small, about one-third trunk length, unbranchedand transparent (Fig. 9A). Narrow anteriorly but considerably dilated and sac-like posteriorly. Ciliated funnels minute, stalked, sparsely distributed oversurface of both vesicles. Gonoducts. Gonoducts two pairs (Fig. 9B), posterior to ventral setae, oval injuvenile specimen but elongate, tubular and considerably distended in sexuallymature individual due to presence o
Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . consisting of fine sand particles (Fig. 9A). Rectalcaecum small, spherical. Anal vesicles. Anal vesicles small, about one-third trunk length, unbranchedand transparent (Fig. 9A). Narrow anteriorly but considerably dilated and sac-like posteriorly. Ciliated funnels minute, stalked, sparsely distributed oversurface of both vesicles. Gonoducts. Gonoducts two pairs (Fig. 9B), posterior to ventral setae, oval injuvenile specimen but elongate, tubular and considerably distended in sexuallymature individual due to presence of numerous ova. Gonostomal lips thin,spirally coiled; gonostomal openings basal in position. Blood system. Intestinal ring sinus is an incomplete vascular ring at posteriorend of foregut (Fig. 10). Dorsal vessel prominent, continuing anteriorly andentering proboscis. Paired neuro-intestinal vessels short, stout, forming smallloop around interbasal muscle (Fig. 10). Heart conspicuous at posterior end ofdorsal vessel. Ventral vessel terminating posteriorly in rectal 3 mm Fig. 10. Ochetostoma formosulum. Anterior part of the trunk cavity,showing the blood vessels. 50 ANNALS OF THE SOUTH AFRICAN MUSEUM Remarks Ochetostoma formosulum (Lampert, 1883) was described from a singlespecimen from Manila, Philippines. This species was later recorded and describedfrom several other localities in the Indo-West-Pacific Ocean. Wesenberg-Lund(1963) recorded and described a single specimen collected from a centralsandbank in Durban Bay. Although this species is fairly well known, somefeatures require further discussion. The most important distinguishing features of O. formosulum are thepresence of two pairs of postsetal gonoducts with spirally coiled gonostomal lips,a very thin and transparent integument, 6-8 longitudinal muscle bands and aninterbasal muscle that passes through a loop of the neuro-intestinal vessel. Othertaxonomic features include the proboscis which is less than one-qua
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
