ARABELLA TRICOLOR, 



397 



South Africa ; Japan ; Juan Fernandez ; Straits of Magellan. May yet be found on the 

 American shores. 



Head slightly flattened from above downward, bluntly conical, and of the same 

 pinkish iridescent hue as the rest of the body. It is distinctly separated from the peri- 

 stomial segment both dorsally and ventrally. At the posterior border it bears four eyes, 

 one on each side of the middle line, and very slightly in front of the others, which are 

 lateral and less conspicuous. The under surface of the snout (Plate LXII, fig. 8) has a 

 longitudinal furrow, probably in connection with the eversion of the proboscis. The 

 mouth opens just behind the prostomium. Two well-marked furrows pass backward 

 from the oral border on each side of the median line, and there is a shorter lateral one. 



Body 8 — 10 ins. long, and with 178—200 or more segments, firm, rounded, often 

 thrown into a spiral. The first two segments are evenly rounded, whereas in the 

 succeeding the feet cause a dimple at the side of each. The first segment is narrower 



nc vm 



Fig. 81. — Transverse section of Arabella iricolor, about the anterior third. The nerve-cord has been pushed 

 inward by the largely developed ventral longitudinal muscles. Letters as before. 



than the second dorsally, but broader ventrally, and proportionally deeper anteriorly. 

 The body is slightly tapered in front, and more distinctly so posteriorly toward the tail, 

 which has the anus at the tip, a kind of funnel being formed by the four short cirri, the 

 tips of which are nearly on a level (Plate LXII, fig. 8 d) } The general colour is 

 iridescent pinkish, with a tinge of reddish here and there from the blood-vessels. 



The proboscis is armed with a series of five brownish-black teeth (Plate LXII, figs. 

 8 6?, 8 b). The maxilla are short, strongly curved, and massive at the base, the inner 

 edge of which is denticulated (eight and nine points). Behind are two tapering pro- 

 cesses with an enlargement immediately behind the maxillas, then a contraction, followed 

 by another enlargement with a spur, the narrow end being continuous with two long 

 parallel blackish rods, which gradually diminish posteriorly and end in slight enlarge- 

 ments. The great dental plates have each eight or ten recurved teeth. The antero- 

 lateral plates are situated on each side of the middle line in front of the maxillas. The 

 posterior plate has four to five well-marked recurved fangs, the first and the third being 

 1 Reference to this figure has been omitted in the description of the plate. 



