124 CELETOPTERUS VARIOPEDATUS. 



ninth is considerably shorter. All except the fourth possess the same armature of bristles, 

 which, from the curvature of the foot (the line of the bristles being on the convexity), are 

 thus brought into contact with the wall of the tube. At the free extremity of the 

 setigerous region are one or two bristles having long, slender, tapering tips with a trace 

 of a wing, thus indicating the type of which the others below it are modifications (Plate 

 CII, figs. 5, 5a and ha'). The tip gradually flattens into a thin, translucent, yellowish 

 blade shaped like a pointed spatula, and the shaft increases in thickness till, at the inner 

 or ventral end of the row, the organ is almost foliate at the tip, and is not quite sym- 

 metrical (Plate CII, figs. 5 b, 5 c, 5 d, 5 e 9 5/). As De St. Joseph and Mr. Crossland l have 

 pointed out, such a bristle has little piercing power, but is admirably suited for applica- 

 tion to the inner surface of the tube as a flexible brush and lever. They are arranged in 

 the foot (Plate CII, fig. 5 g) in the form of a long fan of bristles, the shafts of those at the 

 tip, that is at the extreme outer border of the fan, crossing the shafts of those at the 

 concave or dorsal edge of the foot (Plate CI, fig. 2). The seventh or eighth appears to 

 possess the longest row of these bristles. 



In addition to the foregoing (dorsal) series the fourth foot has ventrally a row of stiff, 

 chitinous, tooth-like bristles (eight) of a deep brown colour. The brown shaft dilates at 

 the tip, and is strengthened by a thick coat of chitin, whilst one edge of the truncate tip 

 is prominent, the whole forming a tooth-like process (Plate CII, figs. 5 h and 5 i) fitted 

 either to act as a lever or as a support. In the row in any individual the tips vary, the 

 stronger being dorsal and the less robust ventral or inner, and they also show age- 

 variations. 



The ninth foot, from its size, has a considerably shorter row of the ordinary bristles, 

 but they do not diverge in structure. Moreover, a hatchet-like (De St. Joseph) ventral lobe 

 is appended to its inner edge inferiorly. This bears an armature of hooks (Plate CII, 

 figs, hj and 5 h), which have an elongate form like those of the Ampharetidse, and show 

 as a rule eight recurved teeth and a rounded " prow " for the attachment of the larger 

 ligament. Some (Herm, Cornwall, etc.) have a minute ninth fang at the commencement 

 of the series. 



Whilst the dorsal surface is distinguished by its narrow median grooved band, which 

 (as a grooved band) is continued on the tenth bristled segment, the ventral surface forms 

 a large convex, glandular, shield-like area somewhat resembling that in Sabella, and in 

 the Neapolitan examples the area is more definitely outlined, probably from the method 

 of preparation. 



The middle region consists of five segments, though it may be a question whether 

 the first, viz. that with the great wing-like lobes, does not pertain as much to the anterior 

 region. This segment has dorsally the median grooved band (ciliated) which has the 

 same diameter as in front, but at the posterior edge of the wings it diminishes and is 

 continued thereafter as an undivided smooth band. Moveover a whitish convoluted 

 triangular mass with its base applied to the grooved band, and its twisted apex extending 

 more than half-way along the great wing, occupies the dorsum of this segment, and 

 appears to represent the secretion of the region. The feet of this segment form great 

 alar expansions of which the anterior half in each is supported by a large fan of bristles, 



1 ' Proc. Zool. Soc.; 1904, i, p. 271. 



