SIBOGLINUM MERIDIALE 231 



Material: one tube containing a complete animal. 



Locality: the northern part of the Coral Sea (the Solomon Sea) near the 

 south coast of New Britain (6°S 150°E), in the British Solomon Islands. 

 Depth: 2028 m. 



14. Siboglimim meridiale Ivanov (Fig. 118) 

 Ivanov, 1960c: 5, 27, 98, 127, 166-7, 197, 264, Figs. 87, 118. 



A common representative of the genus Siboglinum in Antarctic waters is 

 undoubtedly that described under the name S. meridiale. Tubes of this 

 species were amongst the collections of Pogonophora made in 1957 by 

 R.V. OF, and were found at several stations in dredgings taken in the Indian 

 Sector of the Antarctic at depths of 200-1200 m. Amongst a number of tubes, 

 only three were found containing animals, and unfortunately these were so 

 badly preserved as to make it impossible to describe them fully. Certain 

 features, however, obvious even in defective material, and also some pecu- 

 liarities of the tube, make it possible confidently to give a diagnosis of this 

 species. 



The fore-part of the body is long, eight or nine times as long as broad, and 

 the boundary between the protosoma and the mesosoma is not apparent. The 

 cephalic lobe is small and the long slender tentacle, lacking pinnules, is 

 attached not far from the front end of the body (Fig. 118/4). The extra- 

 ordinarily long, delicate, light yellow keels of the bridle, which lies at or just 

 in front of the middle of the anterior section, are fused ventrally but do not 

 meet dorsally. The boundary between the mesosoma and the metasoma is 

 marked by a simple transverse groove, and the front part of the metasoma 

 carries small adhesive papillae, without plaques (Fig. 118^4). The number of 

 girdles of toothed platelets is not clear, but the platelets themselves are 

 arranged for the most part in a single row, with an occasional one out of line 

 (Fig. 1185). The front end of each platelet is a little narrower than the back, 

 and the middle is slightly constricted. The small teeth, of which the anterior 

 group is well developed, are numerous (Fig. 118C). The platelets are 12-1 5/x 



Fig. 117. Siboglinum microcephalum: A -girdles and postannular region of the metasoma (girdles 



figured in ventral view); В - front, filmy part of tube; С - tube near the beginning of the rings; 



D - ringed part of tube; E - hind part of tube. 



an - girdles; pa 1 - ventral papilla lying behind the girdles; sc - dorsal glandular shield; v - ventral 



papilla. 



