SIBOGLINUM TAENIAPHORUM 259 



conical cephalic lobe. The long slender tentacle carries a single, rather sparse 

 row of soft pinnules (Fig. 128Z)). The mesosoma is the same breadth all 

 along, and the delicate muddy-brown unobtrusive keels of the bridle, which 

 lies at its front end, are widely separated both dorsally and ventrally, extend- 

 ing along the surface of low, rather narrow ridges (Fig. 128C). Immediately 

 in front of the bridle on the ventral side is a pair of triangular patches of 

 glandular epidermis (Fig. 1285), while behind it extends a pair of rather 

 broad, lateral glandular strips, homologous with the glandular girdles of 

 many other species of Siboglinum, consisting of groups of epidermal cells, 

 filled with granular secretion. On the ventral side of the body, however, the 

 strips turn backwards and extend as broad parallel ribbons almost to the 

 hind end of the mesosoma (Fig. 128/4, 5, С). Between these ribbons runs 

 only a narrow mid-ventral strip of unmodified integument (Fig. 1285). A 

 similar development of these glandular formations of the mesosoma is found 

 also in S. atlanticum. The hind edge of the mesosoma is curved in the usual 

 manner. 



The fore-part of the trunk is considerably narrower than the mesosoma 

 and the adhesive papillae in this region are shortish. In each of them can be 

 seen a single pyriform gland with its secretory duct (Fig. 1285), and not less 

 than 60 pairs of these more or less metameric papillae border the moderately 

 wide ventral sulcus. The narrow dorsal ciliated band begins a little behind 

 the front edge of the metasoma, and between it and the rows of metameric 

 papillae run a pair of longitudinal lateral ribbons of glandular integument 

 (Fig. 128/f). The middle part of the preannular section of the metasoma is 

 richly crowded with single-celled epidermal glands, situated laterally and 

 more especially on the ventral side. Here and there they nearly coalesce to 

 form two almost uninterrupted lateral rows. In the region of the female 

 genital apertures and oviducts these glandular accumulations disappear, so 

 that here, through the body wall, elongated eggs may be seen lying in the 

 oviducts. A little farther back, in the zone of thickened papillae, the glandular 

 tracts of integument begin afresh, on the dorsal side as well as ventrally, but 



Fig. 128. Siboglinum taeniaphorum: A - anterior end of a female from the dorsal, В - from the 

 ventral, and, С - from the right side ; D - part of the tentacle. 



ag - anterior ventral glandular area; с - cephalic lobe; со - dorsal ciliated band;/- keel of the 

 bridle; g/ - pyriform gland seen by transparency; m - muscle bundles seen by transparency; 

 ms - mesosoma ; nits - metasoma ; pa - papillae of the metameric section of the preannular region ; 

 pi - pinnules ; ps - protosoma ; s 1 - groove between the protosoma and the mesosoma ; s 2 - groove 

 between the mesosoma and the metasoma ; sv - ventral sulcus ; t - tentacle ; tg - ventral glandular 

 ribbon of the mesosoma ; tl - lateral glandular ribbon of the metasoma ; vd - dorsal blood vessel 

 seen by transparency ; w - ventral blood vessel seen by transparency. 



