196 



PART II. SYSTEMATIC ACCOUNT 



segment (Fig. Ю2А). A little farther back the intervals between the rings 

 grow shorter until they are little more than chinks, and the rings thicken and 

 gain a dark muddy or brown tint. In each segment, moreover, a few of the 

 anterior rings anastomose with one another to a greater or lesser extent, and 

 between them only tiny, irregular clear patches remain, looking like slots 

 (Fig. 1205). Still farther back from the mouth of the tube the segmentation 

 breaks down, the intervals between the rings become greater, and each ring 

 splits into two. This part of the tube with split rings (Fig. 102C) is very long, 

 as is also the next portion which is characterized by incompletely fused 



Г" ' .2 



Fig. 102. Siboglinum fedotovi: Tube: A - front part; В - a little farther back; С - middle part; 

 D - hind part. (C and D - after Ivanov, 1957л.) 



