SCOLECOLEPIS. 



155 



each side. Superiorly a short but distinct circular band appears under the conspicuous 

 centra] hypodermic elevation. A fasciculated dorsal longitudinal muscle lies below the 

 foregoing layer on each side, the inferior surface being attached to a firm (chitinoid ?) 

 sinuous band, which forms a space by its upward curve from a raphe. A somewhat 

 triangular interval occurs in the median line between the muscles. The form of this 



nc- 



CTTV. 



Fig. 114. — Transverse section of the ventral wall of Scolecolepis vulgaris, Johnston, before the union of the nerve-trunks. 



arch is maintained by strong transverse fibres, which curve from raphe to raphe. At 

 this point on each side is a kind of rosette of muscular fibres, the chief fasciculi being 

 directed downward and outward in transverse section. Outside the foregoing dorsally 

 are various oblique bands, the superior stretching from the dorsal downward and 

 outward to the lateral hypoderm, while the lateral pass downward and inward. 

 The firm (chitinoid?) arch gradually disappears as the dorsal muscles become fully 

 developed. 



vert" m 



Fig. 115. — Transverse section of the anterior region of Scolecolepis vulgaris, Johnston. 



Behind the preceding region the arrangement consists, as in Nerine foliosa, of the 

 two dorsal and two ventral longitudinal muscles with the interdigitating vertical and 

 oblique bands. No pennate process appears either ventrally or dorsally in the longi- 

 tudinal muscles, as in Nerine foliosa. Whilst the nerve-cords are still separated ventrally, 

 a strong transverse band passes between the attachments of the oblique muscles 

 (Fig. 114). As soon as the nerve-cords meet a large neural canal appears in each 

 toward the inner and lower border, and whilst the increase of the hypodermic area in 

 this region is as marked externally as in the former species, the inner ends of the 



