502 ARICIA LATREILLII. 



ventral edge, but all along the row much stouter spine-like bristles occur, and they are 

 either nearly straight or slightly bent at the tip. Short tapering serrated bristles are 

 present throughout. In the ventral division of the succeeding feet all the curved spine- 

 like bristles are stronger than in A. Guvieri and the papilla have the same character as 

 above. At the twenty-first foot the ventral division has a small group considerably more 

 elongated than in front, but with the terminal curvature, yet no trace of serrations occurs. 

 Even in this, the last of the series, the bristle-like spines are remarkably strong. They 

 are accompanied by the short, tapering, serrated (camerated) bristles. The papillaa 

 remain elongated. The condition of the preparation does not admit of minute description, 

 since the parts are much altered, but the change occurs at the twenty-first foot, which 

 has an elongated ventral cirrus and a tuft of the usual bristles serrated at the tip. At 

 the thirty-first the branchia is fairly large, the dorsal cirrus slightly enlarged in the 

 middle, and a tuft of somewhat stiff bristles serrated at the tip. Between it and the 

 ventral division is a cirrus, whilst the ventral setigerous lobe is bifid and bears a few 

 slender elongated bristles spinous at the tip. The ventral cirrus is subulate. 



The ventral surface is comparatively smooth anteriorly, for none of the rows of 

 papilla) meet in the middle line, those most nearly approaching it being the eighteenth, 

 nineteenth, twentieth, and twenty-first, though some occur laterally from the seventeenth 

 to the thirtieth foot. 



3. Aricia Latreillii, Audouin and Edwards, 1834. Plate LVI, figs. 1, la. 



Specific Characters. — Head as in A. Guvieri. Body 6 — 8 ins. long, pinkish anteriorly, 

 yellowish-white posteriorly, distinguished by having about thirty-one segments in the 

 anterior division ; rows of papillaB on the ventral surface from the twenty-fourth back- 

 ward more numerous than in A. Guvieri. 



Synonyms. 



1834. Aricia Latreillii, Audouin and Edwards. Annel., p. 259. 

 1882. „ „ Mcintosh. Trans. Linn. Soc, Zool., i, p. 504. 



Habitat. — Sandy shores of the Bay of St. Andrews at and beyond low water-mark, 

 and in Laminarian roots tossed on the West Sands after storms. Firth of Forth (J. T. 

 Cunningham) . 



Head acutely pointed, forming a cone as characteristic as in A. Guvieri. 



Body 6 — 8 ins. long, very little tapered in front, and more distinctly so posteriorly, 

 where it terminates in two long slender cirri. In general appearance it resembles 

 A. Guvieri, but the anterior region is composed of thirty or thirty-one segments with the 

 brownish ventral bristles, is somewhat more firm, and the rings bearing papillaB on the 

 ventral surface from the twenty-fourth backward are more numerous. The body is 

 somewhat flattened dorsally or even hollowed in front, and rounded ventrally, and the 

 segments are very numerous — 300 to 400. The proboscis is sometimes ejected as a frilled 

 lobate organ. In life it is of a yello wish- white colour, slightly pinkish anteriorly. 



The body- wall anteriorly is characterized by the great development of the circular 



