KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 63. NIO 7. 17 



not specially strongly stainable, glandular ground. Specimens of average and large 

 size have the same patch filled with large powerful glandular cells (ef. fig. 10); finally, 

 scarcely any original light patch can be suspected. The upper, anteriorly converging 

 glandular bands of the 8 th setigerous segment are exceedingly weak in a number of smal- 

 ler specimens. On the 7 th setigerous segment glands are seen grouped along the sides of 

 the ventral nerve-cord, as on the posterior segments, which, in addition, besides evenly 

 spread glands show them mainly round the parapodia. On the most posterior setiger- 

 ous segments there is a narrow dorsal band of glands between the parapodia; this band 

 increases in strength towards the posterior end. Running round each of the posterior 

 achaetous segments there is a narrow band of glands; in front of the anal cirri there 

 is a somewhat wider one, though ib is rather weak ventrally. Whether the anal cirri 

 in a fully developed condition (unlike what is the case in a more or less weakly re- 

 generated condition) have glands, is uncertain. The anal cone is also quite free from 

 glands in all specimens. 



Setae. The uncini of the l st — 3 rd setigerous segments are not changed to any 

 great extent, although they are very much open especially on the first and even on the 

 2 nd setigerous segment. Bristles have been observed in smaller specimens at least on 

 the lowest uncinus of the l st setigerous segment (text-fig. 3) and in larger specimens even 

 on the corresponding uppermost uncinus. On the 3 rd setigerous segment the uncini are 

 already fairly fully developed. The structure of the developed uncini is seen in text- 

 fig. 4; ef. also Mc Intosh (31, fig. 7 b- c). The bristles are situated close beneath the 

 large tooth and as many as 5 have been observed. The 2 nd tooth seems in a number 

 of setae to be somewhat narrower than the following one. In a specimen about 

 60 mm. long, which was mainly used for the study of the setae, the l st — 18 th setigerous 

 segments had the following numbers of uncini: 2-3, 2—3, 5—6, 10, 9, 11, 13, 12, 14, 

 14, 13, 13, 15, 16, 17, 19, 17, 13. A large specimen has on the l st — 3 rd setigerous seg- 

 ments: 2, 6, 8 uncini. The numbers of the teeth were: 5 — 6 1 , 6 2 , 6— 7 3 , 7 4 , 8 5-8 , 

 8_9 9 - 16 , 8 17 - 19 . 



The borders of the anterior capillary setae are visible only on the foremost seg- 

 ments: only a very narrow one is to be seen on the lst_4.th_.5th setigerous segments, 

 most distinct on the 2 nd — 3 rd . The other somewhat stronger, although exceedingly 

 fine, börder follows the former one in its variations, but is still visible at least on the 

 6 th setigerous segment. The pencil of bristles at the point of the setae is almost imper- 

 ceptible on the l st setigerous segment, weak on the 2 nd — 3 rd but then distinct, especially 

 from the 5 th . The anterior capillary setae on the 8 th — 13 th setigerous segments differ 

 from this usual type. As the material, however, did not allow a more detailed investi- 

 gation of these setae, it may here be referred to the corresponding setae of L. leio- 

 pygos, which are very similar. It is still somewhat uncertain whether there is in _. 

 johnstoni so great a difference in size between the anterior capillary setae as in L. leio- 

 pygos. Their borders, especially on the foremost of these segments, are exceedingly fine 

 and diffuse — almost imperceptible. A beginning of a pencil was only observed in ex- 

 ceptional cases in any of these posterior segments. On the 8 th — 10 th setigerous seg- 



K. Sv. Vet. Akad. Handl. Band 63. N:o 7. 3 



