126 Proceedings of the Royal Society 
In Scolecolepis vulgaris , Johnst., the body-wall is similarly con- 
structed. Anteriorly the central ganglia of the nervous system lie 
outside the muscles on the dorsum, and the cords rapidly pass 
downward to the inferior attachments of the oblique muscles. In 
this region there is also a dense mass of longitudinal muscles. As 
soon as the oral aperture is completed posteriorly by the frilled 
hypoderm, the following arrangement occurs : — Within the hypo- 
derm is an irregular circular coat, the most conspicuous part being 
a broad belt, which hounds the mouth at the ventral border, and 
stretches between the great longitudinal muscular masses on each 
side. Superiorly a short but distinct band also appears under the 
central hypodermic elevation. A fasciculated longitudinal muscle 
(dorsal) lies below the latter on each side, its inferior surface being 
attached to a chitinous sinuous band, which forms a space by 
its upward curve from a raphe. A somewhat triangular interval 
occurs, moreover, between the muscles in the median line. The 
form of this chitinous arch is maintained by strong transverse 
fibres, which curve from raphe to raphe. At the latter, on each 
side, there is almost a rosette of muscular fibres, the chief fasciculi 
being directed downward and outward in transverse section. Out- 
side the foregoing dorsally are various oblique bands, the superior 
stretching from the dorsum downward and outward to the lateral 
hypoderm, while the lateral pass downward and inward. The 
chitinous arch gradually disappears as the dorsal muscle becomes 
fully developed. Behind the preceding region the arrangement 
consists, as in N.foliosa , of a double dorsal and two lateral longitu- 
dinal muscles, with the vertical and oblique bands, the latter passing 
through the former near the ventral attachment. There is also a 
very strong transverse ventral muscle, with a series of longitudinal 
fibres internally. Each nerve-cord in transverse section presents 
a distinct though small neural canal. The hypoderm, as well 
as the muscles, seems to be more largely developed than in N. 
foliosa , a feature corresponding with the increased size of the 
nerves. 
After the dorsal muscles have expanded into a broad layer, the 
same interlacing with the vertical bands occurs, but the pennate 
muscles and the arrangement of the nerve-cords of this form, but the fore- 
going observations do not interfere with his remarks. 
