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PART II. SYSTEMATIC ACCOUNT 



small cephalic lobe is triangular and much flattened dorso-ventrally. Behind 

 the base of the tentacle there is a clearly defined annular groove which 

 hardly appears to be the hind border of the protosoma (Fig. VV133i?, C). 

 The rather thin long tentacle has a single dense row of pinnules (c. 170/x long) 

 only on the distal half: the proximal half has none (Fig. W133y4). 



The front third of the mesoma is laterally compressed. The bridle lies a 

 little in front of the middle of the mesosoma and its dark-brown keels, 



Fig. VV133: Siboglinum zanzibaricum: A -fore-part of the body from the right, B, from the 

 dorsal, and C, from the ventral side. 



c- cephalic lobe; со - dorsal ciliated band; /-bridle; £- glandular portion of integument; 

 ml - longitudinal muscle fibres; tns - mesosoma; pa - papillae; pg - genital papilla; pi - pinnules; 

 ps- protosoma; s 4 - groove between the protosoma and mesosoma; s 2 - groove between the 

 mesosoma and the metasoma; sv - ventral sulcus; t - tentacle. 



