212 PART II. SYSTEMATIC ACCOUNT 



"The metameric region of the trunk is up to 3 mm long and contains about 

 80 pairs of small papillae in two even rows, separated by a wide ventral 

 sulcus. In two specimens the rest of the preannular region can be seen 

 clearly; it bears about 10 large papillae with curved cuticular bars 15 to 20/x 

 long at their tips. The preannular region is 1 1 to 16 mm long. The two girdles 

 are semiannular and lie close together; each one bears 1 to 3 very irregular 

 rows of toothed platelets, which are about 12/x long and have a small anterior 

 group of teeth and a larger posterior group (Fig. А109£, F). There are some 

 large postannular papillae, with plaques like the preannular ones, fairly widely 

 separated from one another. 



"None of these specimens is sexually mature, but some slides of transverse 

 sections prepared by Caullery, with no station number but, according to his 

 text, from sta. 48 (Caullery, 1944, p. 23, Figs. 87-89), show the genital region 

 of a male animal in a tube 0-22 mm in diameter, which could be this species. 

 The spermatophores, in transverse section, are about 30/x in diameter. 



"The tubes are whitish and transparent with fairly thin walls. The ends of 

 the tubes are ringless and have thinner limp walls but the middle parts are 

 stiffer and have rings which are whitish by reflected light and greyish in 

 transparency, and are narrower near the anterior end of the tube than near the 

 posterior end (Fig. A1092?, C). One fragment, 5 cm long, is completely 

 ringless. None of the fragments is longer than 5 cm and the diameter ranges 

 from 0-17 to 0-29 mm in different individuals, though it is usually at least 

 0-22 mm. 



"The specimens described here differ from Ivanov's (1957, 1960a) 

 descriptions of S. cinctutum in only a few respects : the tube is not more than 

 0-29 mm in diameter, instead of 0-34 mm; the pinnules are rather longer; 

 the bridle keels are brown, not black; the adhesive plaques (bars) are 

 15 to 20/x long, not 30 to 35/x. I do not think that these differences are suffi- 

 cient to separate a new species, but they do justify the placing of the Siboga 

 specimens in a new variety, at least until some intermediate form is dis- 

 covered. This variety, S. cinctutum var. subtile is so named because of the 

 smaller size of the tubes and animals." 



Material: 13 fragments of tubes, ten occupied. 



Localities: Malayan Archipelago: Siboga Stations 52 (Bali Sea, 9°3'S 

 119°56'E), 212 (Java Sea, 5°54'S 120°19'E). 



Depth: 462 and 960 m.] 



