116 AMPHITRITE GIGANTEA. 



main branches, these again sub- dividing more or less dichotomously into a series of 

 terminal filaments. The first is the largest, though all form conspicuous tufts. In life 

 they keep up a constant movement like masses of worms (De St. Joseph). 



The anterior region has seventeen pairs of bristle-bundles which arise from vertically 

 elongated lamellae, the first being opposite the last branchia. A large papilla takes the 

 place of these opposite the second branchia, and a smaller papilla occupies the space 

 between the hook-row and the setigerous process in the following eight segments. The 

 sixteen hook-rows of the region have a glandular belt in front and behind, and the 

 majority show a dimpled or interrupted hook-line, as if cut into sections. 



The longer bristles have straight shafts and well-developed wings, a slight curvature 

 marking the tip, which, moreover, shows a dilatation of the shaft or axis just after the 

 commencement of the wings. Then the wings cease, and a translucent, flattened, 

 serrated, tapering blade forms the extreme tip (Plate CXXVa, figs. 10 and 10 a). The 

 shorter bristles have the same character, but the terminal blade beyond the wings is 

 broader at the base (projecting more distinctly in lateral view, like a knife-blade). 1 



The anterior hooks (Plate CXXVa, fig. 10 b) are characterised by the great length 

 of the base, and by its marked curvature from the posterior ligament to the prow. 

 The posterior outline presents a slight convexity superiorly and a slight concavity above 

 the ligament. Bold striae occur on the upper and posterior part of the neck. The 

 main fang is large, and five or six teeth appear above it in lateral view. The gulf 

 under the main fang is large, curving to the process for the ligament, and again slightly 

 hollowed as it passes below it to the prow. In the first six segments the hooks are 

 m a single row, but in the following ten they are in a double row facing each other. 



The posterior hooks differ in the shorter and broader basal region, the increase in 

 the posterior outline, and the diminution of the anterior curves on each side of the 

 process for the ligament. 



This appears to be the Terebella gigantea of Col. Montagu (1818), for the 

 discrepancies are readily explainable. He rightly gives seventeen pairs of bristles, 

 and his capillary appendages are the tentacles, 5 or 6 inches in length, and the three 

 pairs of branchiae are much ramified. By the first eight joints, which have a broad 

 plate on the back, he evidently means the ventral scutes. He gives its length as 

 16 inches, and states that it is the longest of the species (British): "It inhabits the 

 soil at the bottom of the sea, and seems to be destitute of any case. We found one 

 specimen in the estuary of Kingsbridge at low water ; it discharged an orange-coloured 

 fluid from its mouth in great abundance." 2 His figure for the most part represents 

 the ventral surface and is incomplete posteriorly. It has been supposed that the 

 Terebella constrictor of this author is the same species, but an examination shows that 

 it is not. 



This species was also described and figured by De Quatrefages (1865), under the 

 title of Terebella Edivardsi. The French author considered it the giant of the race on 

 the shores of France. 



1 In De St. Joseph's figure the serrations are at right angles to the axis, and the dilatation of 

 the shaft and other points diverge somewhat from nature. 

 3 ' Trans. Linn. Soc./ vol. xii, p. 342. 



