PAXTHALIS (ERSTEDI. 403 



yet the general structure is so much in accordance with the type in others that the 

 functions in all probability are not very diverse. 



The third foot presents a short subulate dorsal cirrus and a somewhat clavate dorsal 

 lobe, with finely serrated slender bristles. The ventral is a massive but short lobe, having 

 superiorly a small group of bristles of the type of those in the foregoing foot, the spinous 

 regions being slightly bent backward and downward, with prominent rows of spines at 

 the commencement. Beneath are about six short and strong bristles with spear-shaped 

 tips, slightly curved and quite smooth, —in short, the extremities of the typical series 

 without the spines, but with the accessory process at the tip. These cover the main or 

 central region of the foot, with intervals between. From the accessory process at 

 the ventral edge of the foregoing lobe springs a group of more slender bristles of the 

 type of the superior series, with well-marked alternate spines. In ordinary views (in 

 spirit) the serrated concavity of these bristles is directed upward. As Pruvot and 

 Racovitza observe, one or two simple serrated bristles occur at the inferior border of this 

 foot. They probably indicate the original condition of the series. The subulate ventral 

 cirrus extends beyond the fleshy part of the foot. 



The fourth foot has the short slender dorsal bristles under the lobe superiorly. In 

 the ventral division the bristles preserve the same type superiorly, but they have spread 

 a little downward. The tips of the great spines beneath are somewhat longer, and the 

 upper has a slender terminal whip. In like manner the slender inferior bristles have 

 spread upward beyond the two lower strong bristles, their structure, however, showing 

 no marked difference from those of the previous foot. The accessory ventral lobe is a 

 mere notch. 



The fifth foot exhibits no noteworthy change except the increased distinctness of the 

 dorsal lobe, and the same may be said of the sixth. 



The seventh foot agrees with the foregoing, and shows very well the series of 

 globular warts or papillse along the dorsal ridge above the cirrus. There are about eight 

 of the stout median bristles with the enlarged tips and terminal brush. 



The eighth foot inaugurates a change, for, superiorly, the slender bristles with the 

 brush-like tips have appeared in the ventral lobe, while the dorsal division is only 

 indicated by an elevation without bristles. There are about five of the strong median 

 bristles with the filiform brush, while the inferior group of slender forms with the curved 

 spinous tips remain as before. The glandular apparatus for the peculiar secretion 

 commences in this foot, 



The foot and bristles gradually assume the typical condition (Plate XXX, fig. 8), 

 but the foot varies little from the foregoing, presenting a smaller superior and a larger 

 inferior spine projecting in the centre of the median lobe, a rounded process superiorly, 

 then the more prominent median lobe, and an inferior process. The brush-shaped bristles 

 superiorly have very long slender shafts, which slightly dilate distally, then taper and 

 terminate in a point. From the sides of the tapering part a series of long hair-like 

 spines project like a brush (bipennato-penicillatge, Kinberg), the enlarged region at the 

 base having a shorter series (Plate XLI, fig. 15). The hair-like bristles either form a 

 hair-pencil, as in the figure, or a broader brush at the tip. These bristles occupy about 

 the upper third of the median lobe. Eight or nine strong aristate bristles then follow, 



