58 



T.G. PILLAI AND HA. TEN HOVE 



Table 5 S. ypsilon sp. nov. Measurements (mm) and counts. 



Total length 



27.5 



15.6 



14.1 



11.7 



6.3 



6.0 



4.6 



Thoracic width 



- 



0.6 



0.6 



0.4 



0.5 



0.5 



0.4 



No. of radioles 



- 



7/7 



8/8 



5/5 



6/6 



6/6 



4/4 



Abdominal length 



25.5 



11.0 



11.3 



8.5 



4.6 



4.3 



2.6 



No. of abdom. segs. 



113 



88 



131 



107 



37 



57 



37 



Capillaries from 



103 



80 



124 



99 



24 



44 



30 



Table 6 S. ypsilon sp. nov. Numbers of radioles. 



Table 9 S. ypsilon sp. nov. from Florida (EJ- 66-460). 



Measurements and meristic data from two longest specimens out 

 of 22 measured. 



Total Thoracic 

 length width 

 (mm) (mm) 



Specimen 1 

 Specimen 2 



No. of Abdomen 



radioles Length No. of Caps 

 (mm) segs. from 



22.7 

 20.7 



0.6 

 0.8 



7/7 

 6/6 



18.5 

 16.7 



110 

 130 



97 

 111 



No. of specimens (n=37) 

 No. of radioles (L/R) 



6 15 13 2 



7/7 6/6 5/5 4/4 



Table 10 Meristic and other data on S. ypsilon sp. nov. from 

 Florida (EJ- 66-460). 



Table 7 S. ypsilon sp. nov. Numbers of thoracic chaetal tufts in 69 

 specimens. 



No. ofspecim. 1 2 1 9 2 2 16 23 3 8 1 1 

 Nos. of. tufts. 10/9 10/8 9/9 9/8 9/7 9/6 8/8 8/7 8/6 7/7 7/6 7/5 



Table 8 S. ypsilon sp. nov. Extent of thoracic membranes in 43 

 specimens. 



Number of specimens 

 Thor. membranes end on 



5 

 6/6 



31 

 6/5 



6 



5/4 



1 

 5/3 



of the radioles (Fig. 6, E). Live material from Stns. 7.D03 

 and 7.D05 showed a pair of pigmented ocelli at the base of 

 each radiole, externally. An operculum is absent; there is a 

 filamentous rudimentary operculumon each side (Fig. 6, E, 

 L, O). 



Two clusters of reddish to reddish-brown prostomial ocelli 

 are present. Although the width of the thorax ranges from 

 0.4-0.6 mm in specimens preserved within their tubes, it can 

 be wider in anterior portions of worms accidentally preserved 

 outside their tubes (Fig. 6, F-H, L-O). The median lobe of 

 the collar is sub-rectangular, rounded laterally and with a 

 smooth mid-ventral notch, giving the entire collar a four- 

 lobed appearance (Fig. 6, F-H & L-O). 



The numbers of thoracic chaetal tufts on the two sides 

 range from 5 to 10, and may be symmetrical or asymmetrical, 

 as are the endings of the thoracic membranes (Tables 7 & 8). 

 Paired thoracic glands are absent. 



Collar fascicles bear up to about four fully developed 

 bayonet chaetae and two more being formed deep within the 

 fascicle, with a similar number of simple bladed chaetae. 

 Juveniles possess fewer, often two fully developed bayonets 

 and two more being formed within the fascicle. Each bayonet 

 chaeta has a long serrated blade, a short unserrated notch, 

 and few to several moderately large somewhat conical teeth 

 with smooth tips on its basal boss (Fig. 7, A-E, F-I). The 

 serrations of the blade are short towards its proximal part. 



No. of specimens 



(n = 14) 



No. of radioles 



4 

 7/7 



2 

 7/6 



4 

 6/6 



1 

 6/5 



2 

 5/5 



1 



3/5 









No. ofspecim. 



(n = 29) 



No. of th. chaetal 



1 

 10/9 



1 



10/7 



1 

 9/9 



4 

 9/8 



6 



8/8 



9 



8/7 



4 



7/7 



2 

 7/6 



1 



7/5 



tufts 





















No. of specimens 



(n = 20) 



Thor. membrane 



1 



7/5 



1 



6/5 



10 



5/5 



7 

 5/4 



1 



4/4 











ends 





















but somewhat pilose distally. Thoracic uncini are mostly with 

 6 teeth, but some have 4 or 5 (Fig. 7, J). Anteriorly there are 

 up to 4 flat trumpet chaetae in each bundle, posteriorly there 

 are 1 or two capillaries instead. Anterior abdominal uncini 

 usually have 4 or 5 teeth arranged in a single row (Fig. 7, 

 K-M). The posterior abdominal uncini are rasp-shaped, with 

 a single anterior tooth and several (4-6) rows of teeth 

 posterior to it (Fig. 7, O). In between, there is a progressive 

 reduction in the number of teeth in a single row, and a 

 corresponding increase in the rasp-shaped area (Fig. 7, N). 

 The special adaptations of the body of the worm in relation to 

 the internal structures of the tube are as follows: A narrow 

 longitudinal groove extends along the mid-dorsal line of the 

 abdomen and thorax (Fig. 6, C, D, H-K, O). The abdomen 

 and thorax are also grooved ventrally, and within this longitu- 

 dinal groove, forms a cord-shaped longitudinal ridge (Fig. 6, 

 C, D, I-L). The orientation of the worms within their highly 

 coiled tubes is such that the dorsal groove is applied to the 

 serrated dorsal ridge of the tube, and the cord-shaped ventral 

 abdominal ridge fits into the gutter-shaped part of the 

 Y-shaped ventral ridge of the tube. The latter, in turn, fits 

 into the ventral groove of the body. 



Collections from the western Atlantic. 5. ypsilon has 

 also been collected from Florida, Bermuda and Aruba. 



Study of material from Florida (EJ- 66-460) provided the 

 following data: The external diameter of the tubes attains 

 1.1 mm. A granular overlay is present. The external coloura- 

 tion varies from faintly creamish to faintly pinkish. Their 

 internal colouration and structures are similar to those from 



Fig. 8 Spiraserpula paraypsilon sp. nov. A, Tube from Curasao, NA, Cornelisbaai, showing granular overlay and longitudinal ridges. B-N. 

 From Klein Bonaire Stn. 2105A. B, Tube with indistinct longitudinal ridges. C-N, From holotype. C, Tube fragment showing serrated 

 dorsal ridge along convex wall. D, Tube fragment with Y-shaped ventral ridge along opposite wall. E & F, Adult worm; E, Radioles of 

 both sides, with very long pinnule-free tips and lacking rudimentary opercula. F, Body showing dorsal and ventral longitudinal abdominal 

 grooves and ventral pigment patches. G-L, Bayonet collar chaetae. M, Thoracic uncini of holotype showing lateral denticles. N, Anterior 

 abdominal uncini, with more prominent denticles. 





