22 IVAR ARWIDSSON, SYSTEMATIC NOTES ON SOME MALDANIDS. 



of these uncini has bristles. Text-fig. 7 shows the uncini, as they appear in the main 

 from the 4 th setigerous segment inclusive. At the upper teeth there are in fully developed 

 uncini some secondary teeth on both sides. Bristles, to a number of 4— 5, are situated 

 close beneath the large tooth. A larger specimen has on the l st — 14 fch setigerous segments 

 the following numbers of uncini: 3, 2, 3, 11, 11, 13, 14, 13, 17, 17, 17, 19, 19, 20 

 and a smaller one has on lst_i()th setigerous segments: 1, 1, 2, 10, 11, 11, 13, 10-11, 

 14—15, 14. Number of teeth: 2-3', 5 2 , 6 3 , 6-7 4 , 7 5 " 6 , 7-8 7 ~ 9 , 8 10 " 11 , 8--9 12 " 15 , 8 16 ~ 24 . 



The anterior capillary setae are, apart from those on the 9 th — (about) the 14 th 

 setigerous segments, furnished with at most very weak borders and, at least from the 

 2 nd setigerous segment, with a distinct pencil of bristles at the point. There are narrow 

 borders on the lst_2nd setigerous segments, but on the following segments they prac- 

 tically disappear. The pencils of bristles, which increase somewhat in strength to the 

 6 th — 7 th setigerous segment inclusive, are elongated and very distinct; the width of the 

 setae below the pencil is 4,5 jj, on a large specimen. On the 8 th setigerous segment a num- 

 ber of setae were observed, which, somewhat below the point, had the pencil developed 

 only on one side. On the 9 th setigerous segment this type of seta is replaced by quite 

 a different one. The upper setae of this other type are considerably coarse. A short 

 way from the proximal end of the free seta there begin (text-fig. 8) in a very character- 

 istic way, exceedingly fine, one may say diffuse, borders, each of which are as wide as 

 the very fine stem here; the total width in a rather large specimen is 12 p.. Distally these 

 borders have a f airly similar course, practically disappearing towards the extended point. 

 An indication of a pencil of bristles can be seen at the distal end of one or more setae. 

 Below the borders (ef. text-fig. 8) the stem widens, attaining here a width of 17 jt and then 

 narrowing again towards the innermost part of the parapodium. These coarse upper 

 anterior capillary setae were observed on the 9 th — 14 th setigerous segments; on the an- 

 terior and posterior segments respectively they probably decrease somewhat in number. 

 On the ll th setigerous segment 11 were counted. Whether there are any similar setae 

 on the 15 th setigerous segment cannot be decided from the material at hand; in any case 

 the lower and smaller anterior capillary setae on this segment are of the usual type and 

 the same is true of all the setae from the 16 th setigerous segment inclusive. The lower 

 anterior capillary setae on the 9 th — 14 th setigerous segments resemble the upper ones, 

 but are finer and decrease downwards rather considerably both in width and length. 

 The fine, diffuse borders do not disappear towards the point as on the upper setae but 

 pass into a pencil of bristles that is generally rather distinct, if not specially long. The 

 points are not specially long. In addition there is no definite boundary between these 

 upper and lower anterior capillary setae, and on a large number of the middle setae 

 there are rather long points without borders and at the same time a rather long pencil 

 of bristles. The lower fine setae are rather numerous and densely situated even from 

 the 9 th setigerous segment. On the ll th setigerous segment 10 were counted, i. e. a 

 total of 21 anterior capillary setae (ef. above) compared with about 16 posterior capillary 

 setae. On the wholc the number of anterior capillary setae is distinctly increased in 

 the segments provided with such setae of differing type. 



The borders of the posterior capillary setae are distinct on all segments, although 



