394 ARABELLA. 



processes. Moreover, the inner edge of the base is furnished with teeth, three of which 

 are visible in front. The great dental plates are elongate, black, and nearly rhomboidal. 

 They have about six recurved teeth along the inner edge besides a considerably larger 

 first fang. The small antero -lateral plates are three in number, each with a long sharp 

 fang, the largest, in addition, having a small tooth at its base, and thus the arrange- 

 ment materially differs from that of A. tricolor, which has in each plate five or six 

 teeth. The mandibles (Plate LXII, fig. 7 b) are dark brown, horny, and wedge-shaped. 

 The broad anterior edge is rounded and roughened. A slight slope occurs on the inner 

 edge of each, running to the point of contact of the halves. 



The first foot forms a simple conical lobe, without marked indication of the process 

 for the bristles as in the second and subsequent feet. It bears a group of simple tapering 

 winged bristles. Very soon a dorsal process or papilla appears, so that at the sixth foot 

 it forms a prominent structure in certain views (Plate LXXIV, fig. 4). The typical foot 

 has a similar outline, viz., a small dorsal lobe sloping outward and upward, a short 

 setigerous lobe projecting straight outward, and a broadly lanceolate inferior lobe directed 

 upward and backward, its longer outline being inferior. Four or five spines support the 

 foot anteriorly (tenth) ; five occur at the thirth- seventh, and posteriorly four or five are 

 present, in addition to a large stout spine, apparently below the others, the tip of which 

 (enclosed in the tissues) is pointed (Plate LXXXIII, fig. 1) and solid. It is a brittle, 

 chitinous structure like the teeth and gives way when compressed. The great strength 

 of this spine in contrast with the others is noteworthy, and apparently its function is 

 similar to the great hooks of the Eunicidae. The bristles (Plate LXXXIII, fig. 1 a) are 

 simple — tapered and winged — with moderately long points, and have the usual oblique 

 striae on the wings. The dorsal are somewhat stronger than the ventral. In glancing 

 along the feet anteriorly the prominent lobe is seen to be ventro-posterior in position. 



Habits. — This species seems to inhabit sand or sandy mud at the bottom, yet the 

 number of specimens procured in the stomach of the haddock by my mother seems to 

 indicate that it occasionally leaves its retreats to crawl about on the bottom, or even to 

 swim in screw- coils over it, though it may also be ejected by storms. 



This form seems to be closely allied to the Drilonereis (Laranda) longa of Webster, 

 from the Virginian coast and New Jersey. Discrepancies may be due to imperfections in 

 description. The example procured by the s Challenger ' was obtained off the American 

 coast between Halifax and New York. The British form differs in the larger size of the 

 dorsal process and in the presence of eyes, but it has been thought unnecessary to 

 constitute a new species. 



Genus LXVI. — Arabella, Grube, 1851. 



Conical head devoid of appendages, but with eyes. Body with two footless segments 

 anteriorly, 1 and finely iridescent. Terminal segment bilobate. Four anal cirri. Proboscis 

 with two strong maxillae ; a great dental plate and three others on each side, the two 

 anterior having long, sharp teeth. Mandibles short with wide anterior plates. The 



1 Grube terms the buccal segment biannulate, the second produced mferiorly to the mouth. 



