and their Position in the System of the Annelida. 397 



which I possess are 1'3 line in thickness and more than 2 inches 

 in length. In the same way the number of segments varies, in 

 accordance with the size, from thirty-three and forty-five (in the 

 small Copenhagen specimens) up to sixty and eighty-two; in 

 all the males examined by Van Beneden, Oersted, and myself, 

 it is on the eighth and ninth segments that the peculiar, large, 

 crooked ventral setae occur, and in the ninth that the sexual 

 orifice and the testis are situated*. In the number of bristles 

 there is a remarkable diversity. Van Bencden gives eight as the 

 normal number both in the bundles of setae and in the transverse 

 rows of uncini. I counted in the Copenhagen specimens never 

 more than four or five, in many Belgian ones twelve, and in the 

 Greenland specimens twelve or more seta?, and far more than 

 twelve (even nearly thirty) uncini, of which, however, those 

 standing nearest to the median line of the ventral surface were 

 scarcely distinguishable, whilst in the opposite direction they 

 increase considerably in length. As the smallest number of 

 bristles belongs to the smallest specimens, it may easily be sup- 

 posed that the number increases with the growth ; and in these 

 diversities, as in those already mentioned, I see no inducement 

 to the assumption of two species, but rather believe that the 

 Capitellce of the Baltic, like many other animals which it has in 

 common with the North Sea, do not attain such large dimensions 

 as in the latter. 



I must further indicate that DalyelFs Lumbricus capitatusf 

 does not belong here, but that the Lumbricus capitatus described 

 by Johnston J, the length of which was from 3 to 6 inches, is the 

 same species, and that he also united with it his previously de- 

 scribed Lumbricus littoralis^, which he had characterized as 

 "aculeis uniserialibus." That he assumed for the blood, the 

 very irregular ebb and flow and grumous masses of which 

 also struck him, two lateral vessels situated between the intes- 

 tine and the wall of the body, may be easily excused if he did 

 not perseveringly observe. He himself says that the movement 

 of the blood appears to depend upon the movements of the body 

 and the extension of its segments. The synonym of Lumbricus 

 fragilis, Mull., which is now recognized as a Scoloplos, is only 

 cited by him with doubt. Our Annelide is also regarded by 

 Fabricius as identical with Olaffsen's L. littoralis minor from 



* Van Beneden's statement of the ninth and tenth segments (p. 17) 

 appears to be a mere printer's error, his figure representing the eighth and 

 ninth as those in question. In a specimen from Greenland, I find these 

 bristles, singularly enough, not on the ventral, but on the dorsal surface ! 



t The Powers of the Creator, vol. ii. 1853, pi. 17. figs. 8, 9. 



"J Loudon's Mag. Nat. Hist. vol. viii. p. 258. 



§ Zool. Journ. iii. p. 328. 



