372 W. A. HERDMAN. 



neighbouring body-wall. Special bundles are also attached to 

 the inner ends of the genital setse, which project freely for the 

 greater portion of their length into the coelomic cavity. 



Mesenteries containing delicate muscle-fibres project inwards 

 from various points on the body-wall, and sling the loops of the 

 alimentary canal in position (fig. 15). The mesenteries are deli- 

 cate and silky in appearance, and are much folded and crumpled 

 so as to be wisp-like. This appearance is partly caused by the 

 thickening of the coelomic epithelium in irregular ridges 

 and masses on the mesenteries (fig. 12). The end of the 

 mesentery which arises from the body-wall is clear, trans- 

 parent, and membranous, while the end which is attached to 

 the wall of the gut is grey, opaque, and like a wisp of spun 

 silk (figs. 10—12). 



Alimentary Canal. — The gut is long and much convo- 

 luted (figs. 7 — 9, 15). It can scarcely be divided into 

 regions. The anteriorly placed mouth leads into a pharynx 

 which cannot be called dilated — one of the points in which 

 this form diflFers from Hamingia arctica, D. and K. The 

 gut performs several close convolutions in the neighbourhood 

 of the genital setae, and then stretches backward to the level 

 ^f the posterior ends of the anterior nephridia (uteri), where it 

 again coils upon itself (fig. 9). It then extends backward once 

 more and enters the posterior much convoluted part of its 

 course, in which it runs almost to the posterior end of the 

 coelom, and then forms first one and then another loop 

 directed anteriorly before becoming the rectum, which extends 

 down to the cloacal aperture (figs. 15 and 16). The intestine 

 as a whole is not so wide relatively to its length as in the case 

 of Hamingia arctica. 



Posterior Nephridia. — These dense tufts of white twigs 

 are placed one at each side of the rectum, and open into the 

 cloaca. Each organ consists of a single, central, thick-walled, 

 opaque brown tube, about 12 mm. in length, which gives ofi" 

 an immense number of delicate, opaque, white-coloured twigs, 

 which interlace with one another so as to give rise to the bush- 

 like appearance (figs. 15 — 18). These white twigs, however. 



