12 OPHELIA LIMACINA. 



ridges are pale. The colour appears to be due to the bright reddish hue of the blood. 

 Occasionally a large- example is iridescent bluish. 



When the proboscis is ejected it forms a button-shaped process (Plate XCV, fig. 1 a) 

 of a reddish hue, with a slightly frilled margin and hollow centre, this part being 

 differentiated from the conical glistening basal part (a) of the aspect of the ordinary skin. 

 When the proboscis is withdrawn it forms a long conical muscular organ lying over 

 the alimentary-canal, the base of the cone being at the mouth, the apex posterior. 

 The gullet is succeeded by a large muscular crop or proventriculus, with dark 

 pigment posteriorly at the constriction between it and the next region, and this is 

 followed, after a slight contraction, by a dark stomach, behind which is the intestine filled 

 with sand. 



The ventral longitudinal muscles are proportionately more massive than in Ammo- 

 trypane, but they do not extend so far forward, about a fourth of the anterior region — 

 which is generally more or less dilated — being devoid of them. The ventral nerve-cord is 

 pinkish. 



Along each side of the body is a row of more or less sessile feet. The first is 

 represented by a double tuft of fine bristles, which curve backward at a point exactly oppo- 

 site the mouth, and thirty-four occur behind it, those near the tail sending their long bristles 

 backward like a fringe. The fine cutaneous ridge is interrupted in front of the first foot, 

 and a separate fillet marks the foot anteriorly. Each bristle-tuft then arises from a small 

 papilla behind it. Three entire cuticular ridges occur between this and the second foot, 

 which shows the fillet in front and the two convex processes or papillae behind for the 

 bristles, which are pale golden. In the third foot the fillet anteriorly is bilobecl, and the 

 bristle-papillae somewhat more prominent. Little change occurs till the eleventh foot, 

 except that the anterior fillet soon forms a guard to the bristles in front, and a fillet lies 

 behind, so that the bristles emerge between them. At the eleventh foot the posterior fillet 

 dorsally is much larger, forming a lamella behind the bristles, and from it a long tapering- 

 dorsal cirrus extends, and the cirri are continued on each foot to the posterior end of the 

 animal. 



The segments are marked by a more prominent lateral ridge passing to the edge of 

 the foot, three or four others lying in the flattened pit between them and above the 

 ventral prominence of the longitudinal muscle of the side. 



The dorsal bristles (Plate CIII, fig. 1) are simple and curved, taper to a delicate point, 

 and are marked by fine longitudinal lines. They are considerably longer than those in the 

 ventral tuft, but both have the same curvature (outward and backward), structure, and 

 pale golden colour, and both are somewhat brittle. 



The dorsal cirri or branchiae are of a pale red, and, though of a different shade from 

 the rest of the body, are not conspicuous. The example was perhaps imperfectly 

 preserved, but it did not show the transverse vessels of the organ seen in Ammotrypme. 

 Cilia are probably present as in 0. radiata. 



In the present species a large blood-vessel on the dorsum is formed by the union 

 of the trunks from the intestinal region, and it goes forward to the anterior part of the 

 stomach, where it is joined by two large vessels from the ventral which run obliquely into 

 it. Passing straight forward, it breaks up into three trunks anteriorly. 



