SABELLARIA ALVEOLATA. 25 



the opercular paleas furnished with numerous palpocils. Moreover, the shortness of the 

 firm buccal region posteriorly distinguishes it from S. spinulosa, The sloping inner row 

 of paleas guard an elliptical central space, at the anterior end of which are the frilled 

 dorsal margins of the mouth. Arnold Watson specially alludes to the two leaf-like 

 anterior continuations of the lips which embrace the bases of the buccal tentacles on each 

 side. He finds the processes beneath the opercular paleas longer in the young than in the 

 adult, and their tips have a brush of long hairs, less evident in the adult. The lateral 

 tentacular filaments are eight or nine in number (in the adults ten), and the intervals 

 between them gradually increase from before backward. The appearances of a young 

 specimen in which the peristomial lobes were thrown back at a right angle to the body 

 so as to make the mouth practically terminal suggested to Mr. Watson the view " that they 

 may belong to the first and second segments." The crown is supported on two short and 

 massive pillars, but they are connate at the dorsal margin, the only differentiation being 

 a gap in the circle of papillae and the central line separating the posterior paleas. Looked 

 at from the face, however, a slight incurvation of the margin is observed dorsally and a 

 more distinct one ventrally, where the split between the pillars supporting the crown is 

 very distinct. In this species the marginal papillae surrounding the crown are larger, 

 longer, and more numerous than in S. spinulosa, and are very conspicuous whether 

 viewed from front or rear. 



The outer paleas form a pale golden, translucent, and regular margin to the crown, 

 lying almost horizontally, or with a slight slope upward, and presenting a finely notched 

 continuous edge under a lens. Each palea (Plate CXXITI, fig. 3) is shaped somewhat 

 like a cricket-bat with a long tapering handle and unequal shoulders, the translucent and 

 flattened blade being slightly bent at the tip and generally split into five or six 

 strong curved teeth directed to the front, or that side of the blade with the higher 

 shoulder and slight concavity in outline. The second tooth, which occupies nearly 

 the middle of the blade, is longest, and is followed by three or four smaller. The 

 blade is marked by transverse strias, which are finest on the translucent tip, and a 

 kind of keel occurs near the higher shoulder, for the shaft is more or less rounded 

 or angular, whilst the blade is flattened. The blades at the dorsal edge are a little 

 longer, and their tips show less friction. The middle paleas have slightly shorter 

 blades, the tips of which are sometimes frayed, and the curve in front differs, in so 

 far as a tendency to slope backward distally is noticeable. Those at the ventral edge 

 show the latter feature in a more pronounced manner, the tips are shorter, the teeth at 

 the tip are longer, less curved, and show the effects of friction. The developing paleas 

 in the tissues have the teeth connected by a membrane. Arnold Watson notes that in very 

 young examples the outer paleas much resemble the stout bristles of the thoracic region 

 of the adult. 



The second row, which is nearly horizontal, consists of paleas (Plate CXXIII, fig. 3 a), 

 with an outline resembling a large heavy foot (the blade) and a slender tapering leg 

 (the shaft), the heel being comparatively small. The double outline on the part repre- 

 senting the sole is less marked than in Sabellaria spinulosa, and this outline is nearly 

 straight, the opposite one being slightly convex. Both slope a little toward the blunt 

 tip, which is often frayed. The flattened tip is crossed by transverse strias, and the tips 



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