PBOTINARIA BELGICA. 41 



two segments are glandular ventrally, and in the centre of each is a median fold 

 or boss. 



The next region of the body, which is smoothly rounded dorsally, flattened and 

 grooved ventrally, consists of three bristled segments devoid of hooks. The first two are 

 highly glandular ventrally from side to side, and with the median fold, whilst the 

 third is apparently only partly so, being continued ventrally as a transversely folded 

 band with a slight median differentiation. The bristles in these are typical, viz. strong, 

 with tapering tips (Plate CXXIV, fig. 1), which show traces of wings, and those with the 

 spear-head dilatation and the long hair-like tips, the edge being serrated. 



The succeeding region of the body still remains smoothly rounded dorsally, but 

 ventrally it has throughout the five or six anterior segments a fusiform area in the centre, 

 apparently a special glandular region. At each side ventrally in a line with the lamellae 

 is a short glandular patch, which diminishes as the segments go backward. The 

 ventral surface generally is flattened and grooved posteriorly. This region has fourteen 

 pairs of dorsal bristle-bundles attached to the dorsal edges of the lamellse bearing 

 the rows of hooks. The bristles are stout, simple, with tapering tips which have 

 traces of wings (Plate CXXIV, fig. 1), besides those with spear-shaped dilatations, 

 serrated edges, and long tapering tips. The tufts are smaller posteriorly, but do not 

 differ in structure. 



Each of the hooks (Plate CXXIV, fig. 1 a) presents seven teeth below the crown ; 

 then follows a process with minute teeth, the trend of which is from above obliquely 

 outward, whilst the prow inferiorly is bluntly conical. The shaft of the hook is short and 

 bent nearly at a right angle. In Malmgren's figure of the hook the minute teeth above 

 the prow cover a longer space — that is, are more numerous than in the specimens from 

 Britain. The prow, both in this species and in Amphictene auricoma, often presents a 

 slightly double tip as if not smoothly rounded. 



The tortoise-shaped caudal process is usually bent at more than a right angle to the 

 dorsum, thus making a small angle with the ventral surface. The rudimentary feet pass 

 obliquely upward to the dorsal keel, toward the end of which is on each side a consider- 

 able row of caudal hooks. The dorsal surface of the process is flatter than in allied 

 forms, a median keel and symmetrically arranged transverse ridges being on this surface. 

 The rim is not much elevated, and has two notches beyond the hooks and in some a 

 minute papilla or two. The caudal hooks (Plate CXXIV, fig. 1 V) differ from those of 

 any other form, having a comparatively straight shaft tapering toward the neck, which 

 bends a little backward and then gently forward at the tip, so as to form a strong point. 

 As usual the shaft is longitudinally striated. 



The tube is large, nearly straight, and tapered to a small extremity. Moreover it is 

 lined in some by a comparatively thick internal membrane which readily separates in the 

 preparations from the firm wall. Its masonry as a rule differs from that of Lag is or 

 Amphidene in so far as the grains are smaller, and even though in some the surface is 

 rendered irregular by projecting larger grains, the general effect is characteristic. Typical 

 examples on sandy ground are smooth and finely grained, no separate joints being 

 distinguishable (Plate CXVIII, fig. 4 a). 



On a large example dredged by the " Knight Errant " in Loch Linnhe off Castle 



175 



