298 NEREIS (PERINEREIS) MAEIONII. 



outline. The ventral cirrus arises at its base and extends somewhat beyond it. Its 

 proportions are large. A single spine passes to the furrow between the larger and 

 smaller terminal papillse. 



The tenth foot (Plate LXXII, fig. 3 a) has a slightly tumid upper border with a faint 

 depression at the origin of the dorsal cirrus. The dorsal lobe forms a short, broad cone, 

 and is therefore less blunt than in the first foot. A dorsal setigerous lobe appears as a 

 small papilla below the former, and it bears a tuft of bristles with slender tapering tips 

 and a spinous edge (Plate LXXXI, fig. 3). These have rather shorter tips than in the 

 two foregoing species, viz., N. pelagica and N. cultrifera. Beneath is a somewhat bluntly 

 rounded lobe. The inferior setigerous lobe has the characters mentioned in the first foot, 

 viz., a small dorsal papilla, then a larger blunt process followed inferiorly by a projecting 

 rim under the bristles. The upper bristles of this lobe conform to those of the dorsal 

 division, whilst beneath is a dense group of stout bristles (Plate LXXXI, fig. 3 a) with 

 short tips, which may form a palisade of uniform length. The terminal piece is slightly 

 curved at the tip, and has a less projecting anterior inferior angle than in N. cultrifera, 

 and a spinous edge. The shaft shows two camerated streaks in the centre. The inferior 

 lobe is tongue-shaped with a blunt tip which does not extend so far outward as the 

 setigerous lobe above it. The ventral cirrus is considerably shorter than the dorsal and 

 does not reach the extremity of the ventral lobe. 



The lobes of the foot undergo considerable changes, so that at the thirty-seventh the 

 dorsal becomes both diminished and pointed (Plate LXXII, fig. 3 b), the dorsal cirrus 

 is carried somewhat further outward, and is, compared with the lobe, proportionally large. 

 The upper setigerous lobe beneath is more distinctly seen than in the tenth foot and is 

 bifid. It bears similar bristles. The ovate lobe beneath is also considerably diminished, 

 and does not extend so far outward as the dorsal. The inferior setigerous process has 

 rather increased in lateral view, but projects less, and the distal end is more uniform, only 

 the small papilla at the upper bristles being prominent. The bristles are unaltered. 

 The tongue-shaped ventral lobe is much less, but it approaches the tip of the setigerous lobe 

 above more closely, since the latter is less prominent. The diminution of the foregoing 

 lobes brings the tip of the small ventral cirrus nearly in a line with that of the adjoining 

 lobe. 



At the fifty-seventh foot (Plate LXXII, fig. 3 c) a great development of the region 

 between the base of the dorsal cirrus and the body has ensued, so that the diminished 

 dorsal cirrus with the minute lobe beneath is thrust far outward — as the terminal parts of 

 the great flattened vascular lamella thus formed. The dorsal border is occupied by 

 granular glands (Claparede's granular follicles), and similar opaque matter occurs at its 

 inferior edge. The spine and two bristles mark the dorsal setigerous lobe, but no papilla 

 is visible. The lobe beneath is about the same size as in the thirty-seventh foot. The 

 inferior setigerous lobe is rather less and has fewer bristles. Moreover the upper two 

 or three bristles with short tips have proportionally increased in size. The ventral lobe 

 and the cirrus are somewhat less. 



The elongation of the upper region of the foot is fully developed at the sixty-eighth 

 foot (Plate LXXII, fig. 3 d) where it forms a greatly elongated vascular process, the base 

 of which occupies fully half the foot in lateral view. The region, indeed, forms a long 



