NEREILINUM MURMANICUM 165 



single row in each ridge and often placed two by two. The glands hardly 

 increase in size towards the back of this "metameric region". I have counted 

 the number of "metameric" glands on ten specimens and found them to vary 

 between 62 and 95 on each side of the body. The epidermis of the latero- 

 ventral ridges is extraordinarily rich in gland cells : by transmitted light it is 

 completely obscured because of the presence of a granular secretion in these 

 cells. Thanks to this opacity the transparent pyriform glands stand out very 

 plainly. This glandular epidermis of the metameric region of the metasoma 

 is very like that found in some species of Siboglinum (e.g. S. taeniaphorum 

 and S. atlanticum), where, however, it is confined to a longitudinal glandular 

 band outside the papillae, whereas in Nereilinwn murmanicum it covers the 

 whole latero-ventral surface. The broad dorsal ciliated band is plainly visible 

 and starts almost at the very beginning of the metasoma (Fig. B92Z?, C). 



The "metameric region" only occupies a relatively short stretch of the 

 preannular region; the greater part of this section of the body bears numerous 

 glandular epidermal warts or papillae, very variable in shape and size 

 (Fig. C92A). A zone of thickened papillae is present, formed of 5 to 10 large 

 conical papillae disposed in a single row on the ventral side, one behind the 

 other (Fig. B95i?). They do not bear cuticular plaques. The part of the 

 metasoma between this region and the girdles has no noteworthy features. 



The two girdles are situated close together and both are widely broken 

 ventrally. On each girdle the toothed platelets form two irregular rows 

 (Fig. C92C, Z), E). Behind the second girdle lies a large conical ventral 

 papilla, lacking a cuticular plaque (Fig. C92C). The yellowish toothed plate- 

 lets of the girdles are appreciably narrower at the front end. The anterior 

 group of teeth is well developed but occupies no more than a quarter of the 

 area of the platelet (Fig. C92F), and behind it runs a narrow transverse band. 

 The posterior teeth are much larger and arranged in 8-10 oblique rows 

 (Fig. C92F). The platelets are between 15 and 18^ long. 



The postannular region of the metasoma is long and thin. In most indi- 

 viduals it was macerated and it was preserved in only a few specimens. Along 



Fig. B92. Nereilinwn murmanicum. The front ends of 3 specimens: А, В - a female in ventral and 

 dorsal view; С - a female in dorsal view; D - a male in ventral view. 



с - cephalic lobe ; ci - glandular ring of the mesosoma ; со - dorsal ciliated band ; ep - epidermis ; 

 epg - concentration of epidermal gland cells;/- bridle; g - mesosomal glands; gt - metasomal 

 pyriform glands; ms - mesosoma; mts - metasoma; pg - male genital papilla; 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; vd - dorsal blood vessel. (Ivanov, 1961 д.) 



