AMPHITRITE FIGULUS. 119 



beneath is a globular process followed by the lower lip, which is separated by a groove on 

 each side from the folds or arches. Behind the lower lip ventrally is a well-marked 

 collar with a crenated anterior border stretching completely across the ventral surface in 

 the line of the first branchiae. It has a rounded, free edge dorso-laterally, and a median 

 and two smaller crenations at its posterior border, and these probably usher in the change 

 seen in the next ring, which has a distinct, though small median scute or pad. 



The body is 6 — 8 inches in length, enlarged in front and tapering toward the 

 posterior end, as usual in the family. The segments number from ninety to one hundred, 

 and of these twenty-four bear bristles, the first being opposite the third or last pair 

 of branchiae. The dorsum anteriorly is tessellated in the preparations somewhat as 

 in Scalibregma, each of the two rings in the segments being crossed antero-posteriorly 

 by folds which cut the ring into narrow spaces. On the ventral side of the second 

 branchia is a papilla, the forerunner of the setigerous process which follows in the next 

 segment. Moreover, below each setigerous process is a small papilla, as in A. cirrata, 

 but these are continued for sixteen segments instead of the few in A. cirrata. The 

 bristle-tuft is situated at the posterior part of one ring, whilst the following ring 

 lies between the bristle-tufts. This arrangement, however, extends only throughout 

 thirteen or fourteen rings, viz., from the interval between the second and third branchiae 

 backward. Then the rings are marked by transverse furrows, each being thus divided 

 into two, whilst further backward, as the space between the bristles increases, into 

 a larger number of rings. In some cases the posterior lamellae for the hooks are 

 asymmetrical, an intermediate lamella occurring on one side only. The posterior 

 segments show less regularity in their narrow transverse dorsal furrows. The body 

 diminishes and ends in a terminal anus. The colour of the body is pale orange. 



Behind the first distinct scute, or ventral shield, already mentioned in connection 

 with the mouth, is a narrow elongated one, followed by thirteen others, those immediately 

 succeeding the very narrow one gradually, though slightly, increasing in antero-posterior 

 diameter to the eleventh or twelfth, whilst the last three or four are rudimentary, being 

 rounded or shield-shaped median elevations, which gradually end in a moniliform and 

 somewhat elevated ventral ridge, by-and-by lost in the groove posteriorly. 



The branchiae are three in number, of a fine dark reel colour and slightly mottled 

 under a lens. They coil and twist actively under examination. The first is the largest, 

 the third the smallest. Each springs from a cylindrical base, which soon divides 

 dichotomously, though occasionally a small tuft of three short filaments may be found 

 on the main stem of the first branchia. The terminal branches are long and tapering, 

 and in life these give the aspect of gills formed of simple filaments. Each filament is 

 enveloped in a transparent structureless cuticle, whilst the centre is marked by coherent 

 granular tissue arranged in a close series of transverse rows so as to give the whole 

 a finely barred aspect. No distinct longitudinal fibres are apparent, though in some a 

 longitudinal canal is seen. In the basal region are many large compound bodies — the 

 " blood-globules " of Williams. 



A small conical papilla situated in the groove close to the exterior of the second 

 pair of branchiae marks the commencement of the setigerous processes, though it has 

 no bristles, and it is in a line with the second post-oral fold, in the centre of which 



