340 PART II. SYSTEMATIC ACCOUNT 



little in front of the middle of the mesosoma (Fig. 136Д B), are fused ven- 

 trally and just fail to meet dorsally. The annular groove between the mesosoma 

 and the metasoma is straight. 



The short metameric part of the preannular region of the trunk is not more 

 than two to two-and-a-half times the length of the mesosoma, and the ventral 

 sulcus is feebly developed (Fig. 136A). The 17-18 pairs of comparatively big, 

 metameric papillae are variable in shape, but often transversely elongated. 

 Cuticular plaques are absent from the first one or two pairs of papillae, but on 

 the remainder they look like broadly oval, transverse scales with dark crescentic 

 thickenings along the front edge (Fig. 136/4). As in H. abyssicola, where, 

 however, they are round, these scales reach 2(V in greatest diameter. The 

 dorsal ciliated band is so broad that it takes up the whole dorsal surface, 

 beginning immediately at the front end of the trunk (Fig. 1365). The very 

 long, cylindrical non-metameric part of the trunk is furnished with sparse 

 scattered rounded adhesive papillae, mainly sited on the ventral side (Fig. 

 136/4). Shortly behind the centre of this region they are larger, then become 

 smaller again and characterized by somewhat smaller cuticular plaques, 

 c. 15/x across. The well-developed zone of thickened papillae has 12-13 

 large, conical papillae arranged in a dense, mid-ventral row (Fig. 136C). The 

 oval plaques here are about 25/x across. The two girdles, lying close together 

 on well-marked ridges, are bow-shaped, arching backwards, and interrupted 

 on the ventral side with the ends turned forward (Fig. 136Д E). In most 

 specimens the first girdle is interrupted dorsally also, but in one individual 

 there was no dorsal gap. The mainly biserial yellowish toothed platelets of 

 the girdles, up to 16/x in length, are comparatively narrower than in H. 

 abyssicola, but furnished with larger and longer teeth. The small group of 

 anterior teeth is clearly demarcated from the hind group (Fig. 136G). The 

 very long, cylindrical postannular region of the body begins with a pro- 

 nounced waist immediately behind the second girdle, and then all along it 

 small adhesive papillae are developed, arranged on the ventral side in trans- 

 verse metameric rows of 3-5 each (Fig. 136Z), E). Each papilla bears a trans- 

 verse, rod-shaped, slightly curved, adhesive plaque. 



To judge by one very nearly complete individual, the body must reach a 

 length of 10 cm. The tentacles are 3 mm long; the fore-part of the body 

 0-8 mm long by 0-2 mm broad; the metameric portion of the trunk is not 

 more than 2 mm long. 



The spermatophore is shaped like that of H. abyssicola, but smaller by at 

 least a third, and, as in the rest of the Pogonophora, it is furnished with 

 a very long, slender filament, with a ribbon-like, transparent base. The 



