252 J. H. ASHWORTH. 



127, and pi. xsxviii, fig. 6) has also figured from Neplithys 

 inermis a forked seta, whicli is similar to those of Scali- 

 bregma, except that the two prongs of the fork are equal in 

 length in the former. 



Furcate setae are also known to occur in the Ariciidae, 

 having been described by Mcintosh (1879, p. 504, and pi. Ixv, 

 fig. 7) in Aricia greenlaiidica, by S. Joseph (1894, pi. v, 

 fig. 116, and 1897, pi. xxi, fig. 172) in A. latreillii and 

 A. laevigata, and by Cunningham and Eamage (1888, pi. 

 xxxviii, fig. 7e; pi. xl, fig. 8 d) in Scoloplos armiger and 

 Theodisca mammillata. The setae of these worms are, 

 however, evidently quite diiferent to those of Scalibregma, 

 the fork of the former not being fixed quite so symmetrically 

 upon the shaft, and the tips of the prongs are not fine and 

 pointed, but slightly thickened. 



Furcate setse, agreeing in essential characters with those 

 of Scalibregma — that is, possessing unequal barbuled and 

 finely pointed prongs, are practically confined to the genera 

 Eumenia, Lipobranchius, and Scl erocheil us, which on 

 other grounds have been placed with the genus Scalibregma 

 in the family Scalibregmidae. 



7. Skin. 



In the anterior and inflated portions of the animal the 

 annuli bear longitudinal grooves on their dorsal and lateral 

 regions, which subdivide the skin into a series of squarish or 

 oval elevations (fig. 5). These are due chiefly to the fact 

 that the epithelial cells which form them are elongated, 

 columnar cells, while those of the grooves are much shorter, 

 almost flattened cells. Many of the cells of the papillas are 

 club-shaped, mucus-forming cells, which stain deeply with 

 haematoxylin (for other glaiids of the skin and cirri see pp. 

 247 — 249). These cells do not occur in the intervals between 

 the elevations (fig. 12). In some specimens in which there is 

 an excessive amount of inflation of the body, the skin of the 

 inflated region is almost transparent. Behind this region 



