62 



specks, however, are visible externally at the base of the collai 

 on each side. The great setre occur on the 4th segment and 

 are modifications of ordinary bristles for special work (Plate V, 

 fig. 51). They are of great size, widened at the tip and 

 specially thickened by the chitinoiis secretion there, a feature 

 well seen in forms which have not yet been worn. These, as in 

 the figure, have the tip on one side acute, and, moreover, the 

 edge is minutely serrated, as if to show its connection with the 

 ordinary forms. These serrations disappear in those subjected 

 to wear. Considerable variation in size occurs in representatives 

 of the species from different quarters, thus in some Neapolitan 

 examples these bristles are considerably smaller (Plate V, fig 52 j, 

 but they retain their essential characters. 



In the sickle-shaped anterior feet, again, the bristles present 

 a characteristic gradation from the slender terminal forms with 

 narrow wings (Plate V, fig. 53) to the spathulate kinds which 

 succeed, and which in varying proportions occur throughout 

 the greater part of the edge of the foot ( Plate V., fig. 54) 

 to the greatly developed series towards the base (Plate V.^ 

 fig. 55) which not onlv have a much larger spathuUte 

 tip, but a thicker shaft, the figures being drawn to the 

 same scale. The flattened and tapered tips of the spathulate 

 bristles have probably special functions in progression, and in 

 the various movements in the manufacture of the tube, just as 

 the powerful bristles of the fourth segment have in these and 

 other respects. 



The hooks of the anterior region (Plate V. fig. 56) and those 

 of the posterior agree with those from European waters, though 

 the figures just quoted may not correspond in all cases. Thus 

 in the able memoir of Joyeux-Laffine these hooks (Arch. Zool. 

 Exp6r. 2d Ser. viii., PL XV., f. 4) are represented by an example 

 which has the processes for the tendons at each end too large, as 

 IS also the tendon itself, and either an unusuallv long hook or 

 one not fully on its flat has been selected for illustration. The 

 French author has correctly indicated a double series of 

 striations on these hooks. In the South African examples the 

 most superficial striations slant downwards and forwards from 

 the posterior border of the hook, whilst by deeper focussing a 

 liner series pass from the teeth obliquely- — with a slight inclina- 

 tion downwards and backwards. 



A former comparison of examples from the various British 

 areas in which it occurs with those from Naples led to the view 

 expressed by M. Joyeux-Lafline,* viz., that so far as these go 

 one species alone is concerned. The same conclusion is 

 reached when the form from the Cape is included, for in all 

 essential particulars it is identical with the European examples. 

 This opinion is shared by Mr. Cyril Crossland, who is doing 



* Arch. Zool. Exper. 2d. Ser. viii. pp. 346-50. 



