10 DR. W. BAIRD ON NEW TUBICOLOUS ANNELIDES. 



the lobe, while the ventral cirrus is shorter than its corresponding 

 lobe. The bristles are of two kinds, — those of the setiferous 

 tubercles being numerous, compound, and consisting of a flattened 

 lancet-shaped blade, smooth and rather sharp-pointed, let into a 

 somewhat cylindrical shaft which is striated half across (set(B 

 cultratcB) (fig. 1 e) . Mixed with these are a few (about four or 

 five) long and stout setse of the falcate kind, but much longer 

 and stronger than those of the anterior feet. 



The species which approaches nearest to this is the Hetero- 

 nereis renalis of Johnston =^. arctica of Oersted. It differs, 

 however, in many respects. The relative size of the first and four 

 succeeding segments, the colour and peculiar markings of the 

 body, the canal running down the centre dorsally and ventrally, 

 the number of anterior segments (in renalis or arctica being only 

 twenty, while in this species there are twenty-one), the posterior 

 portion of the body being more slender, and the tail destitute of 

 cirri, the structure of the feet and cirri, &c., — all separate it from 

 that species. 



The only specimen which I have seen was found by Mr. 

 Laughrin at Polperro, Cornwall, in a muddy bottom, and is now 

 in the national collection, British Museum. 



Description of several new Species and Varieties of Tubicolous 

 Annelides= Tribe Limivoea of Grube, in the Collection of the 

 British Museum. By W. Baird, M.D., F.L.S.— Part I. 



(Plate I.) 



[Read April 21, 1864.] 



In the extensive collection of Annelides belonging to the British 

 Museum, now in course of arrangement, there is a considerable 

 number which appear to me to be undescribed. In many cases 

 these are diificult to determine, from the fact that soft animals 

 preserved in spirits do not always retain their form and consist- 

 ence, or may be so hardened by the spirits as to offer great difB.- 

 culties in making out the different parts. In the case of the 

 Tubicolous Annelides, again, perhaps only the tubes or cases in 

 which the animals dwell have been preserved, and thus it is 

 almost impossible to refer them to their proper genera. As, 

 however, notwithstanding these diflficulties, we possess many 



