LUMBBICONEREIS IMPATIBNS. 381 



ventrally resembles that of L. fragills. The mandibles (Plate LXV, fig. 8 a) form a long 

 narrow wedge on each side, and they are fused along a third of their inner border. A 

 wedge-shaped gap occurs in the centre anteriorly. They are prettily marked on one side 

 by five curved lines of brown anteriorly, and by similar brown lines arranged longitudinally 

 on the reverse side. Considerable variation, however, occurs in the aspect of these organs 

 — probably in connection with regeneration, as may be observed by comparing the fore- 

 going figure with another example (Plate LXII, fig. 2). 



De St. Joseph found a Monocystis in the intestine of one at Dinard. 



The first foot is readily distinguished from allied forms by the occurrence of long 

 hooks with rather narrow wings, and of black spines. The feet in front of the seventh, 

 indeed, show an irregularly conical posterior lobe somewhat like that of L. frag His, and a 

 narrow anterior lobe. There are three black spines. Dorsally are two groups of winged 

 bristles, which have moderately tapered tips. Below the spines is a series of long winged 

 unjointed hooks, the flattened tip of which has parallel sides (Plate LXXXII, fig. 4 a), the 

 drawing in this case being from the first foot and showing a differentiation at the end of 

 the shaft, indicating the morphology of the tip, viz., as a modification of a jointed bristle. 

 The distal end has a series (four) of small hooks, the first and last of which are somewhat 

 larger, but not much. On the front (the convex border) of the distal end of the shaft are 

 indications of minute serrations. 



The winged hooks (Plate LXXXII, fig. 4) with the elongated tips continue to the tenth 

 foot, though even in this there are signs of modification (Plate LXXIII, fig. 10). 1 The 

 dorsal bristles are split into two fascicles and the tips are similar to those in front. More- 

 over, the wings are traceable almost to the tip. The upper group has longer, the under 

 shorter tips. The ventral series of winged bristles (below the hooks) resemble those 

 with shorter tips in the dorsal. In lateral view the posterior lobe of the foot is perhaps 

 more massive than in L. fragills. Four black spines are present. 



At the twentieth foot the structure of the winged bristles is the same, and especially 

 as regards the continuation of the wings on the filiform tip. The flattened distal region 

 of the winged hooks is now considerably shorter, though in antero-posterior view they 

 retain the slight bend seen in front. 



The thirtieth foot has the dorsal bristles in two groups, an upper of stouter winged 

 bristles (Plate LXXXII, fig. 4 b) with a marked curve toward the tip, and beneath these a 

 larger group of more slender bristles (Plate LXXXII, fig. 4 c), the tips being very attenuate. 

 The median series of hooks has now much shorter tips, but the wings remain narrow, and 

 their slightly bevelled condition opposite the point of the hook is still evident. The fang 

 is comparatively small, and above it is a crown of four or five minute teeth (in lateral 

 view). Inferiorly is a group of stout tapering winged bristles like the upper series of the 

 dorsal. The foot has three strong black spines. 



At the fifty-seventh foot only a single bristle of each kind remains above the hooks, 

 which are stouter and now show considerable abbreviation of the tip (Plate LXXXII, 

 fig. 4cZ). The chief fang is larger. The strongest winged hook is above the three black 

 spines. The tapering winged bristles generally disappear about the sixtieth foot, though a 

 single bristle below the two powerf ul dorsal hooks is found occasionally considerably beyond 

 1 The artist has omitted the winged hooks in the figure. 



