208 PART II. SYSTEMATIC ACCOUNT 



missing, but pinnules are present on the distal part of what is left, arranged 

 in a single sparse row. The bridle is well-developed, its rather stout black 

 keels fused together on the ventral side and almost meeting dorsally. The 

 cutaneous ridges of the bridle are imperceptible, and behind the bridle the 

 mesosoma bears an epidermal glandular ridge, forming a belt which is in- 

 terrupted on the ventral side (Fig. 108Д В). 



The metameric part of the preannular region is rather long, with a 

 pronounced ventral sulcus and a broad, dorsal ciliated band beginning at the 

 very front of the metasoma (Fig. \08A). The numerous metameric papillae, 

 forming flat even lateral ridges, are strongly compressed and hence much 

 elongated from side to side. They are obviously glandular and lack cuticular 

 plaques. In one individual the zone of thickened papillae of the nonmeta- 

 meric part of the trunk was dissected out for investigation. Here, eleven 

 large conical papillae were immediately obvious, arranged in a single ventral 

 row (Fig. 109/4). On the tip of each papilla was a slightly curved transverse 

 plaque, about 30-35/x across. The region of the girdles differs greatly in the 

 two individuals. In one of them, to all appearances the more typical individual, 

 the girdles lie on well-marked transverse ridges and are interrupted on the 

 ventral side (Fig. 1095, C). The toothed platelets are arranged in two or, in 

 places, three rows (Fig. 109F). Between the girdles lies a small unpaired 

 papilla, and three similar papillae, bearing plaques, are to be found behind 

 the girdles. In the other individual the girdles are rather strongly stretched 

 (Fig. 109/)). Each forms a broad arch on the dorsal side with the convexity 

 directed forward. The toothed platelets, moreover, are placed in no sort of 

 order, but at the same time are clearly more or less two deep in each girdle. 

 The total effect is of a very strange girdle, quite unlike anything which has 

 been seen in any other species of pogonophore, and, to all appearances, this 

 must represent an extreme individual variant, for it cannot be an artefact 

 of fixation. 



The transparent and almost colourless toothed platelets are elongated and 

 compressed at the front end. Their surface is covered with sharp teeth, 

 pointing straight backwards and arranged in numerous regular oblique rows. 

 On the front end of a proportion of platelets, however, may be observed a 

 small feeble detached portion, which represents the area of the anterior 

 group of teeth and is furnished with small sharp teeth pointing backwards 

 (Fig. 109G). Sometimes this part is far lighter in colour than the rest of the 

 platelet. The platelets are 12-19/x long by 4— 5-5/u. broad. The long slender 

 postannular region of the trunk carries, at equal intervals, a series of large 

 broad dorsal glandular shields (Fig. 109/)). 



