KEPORT ON THE ANNELIDA. 
141 
a diminished state in the subsequent feet, assuming from before backward a more ventral 
position. The arrangement of this curious fold is well seen on viewing the tip of the 
foot directly. It forms a rim extending continuously from the dorsal to the ventral 
margin posteriorly, and then, with a break, passes along the front of the foot to its 
summit, where a sinus again occurs. 
Superiorly the first foot has a comparatively short group of stoutish serrated bristles. 
This division is widely separated from the inferior series, which has superiorly a few 
bristles with numerous joints, and a well-marked claw, with a secondary 2 )rocess at the 
tip. Below is the central series of strong bristles (PI. XIIIa. fig. 9) with short tips, 
likewise furnished with a secondary process. The inferior series, again, approach the 
superior in having numerous joints in the tip, but they are much more slender. Both 
divisions of the foot show numerous long papillae. The ventral cirrus forms a long, 
smooth tapering process which arises near the palpus and has a slightly bulbous tip. 
Proceeding backward, it is found that considerable alteration takes place in the 
structure of the foot. The bristles of the dorsal division (PI. XIIIa. figs. 7, 8) more 
closely approach the ventral. The superior and inferior bristles of the ventral series 
(with many-jointed ends) are generally absent, only the stout central bristles remaining, 
and their tips are reduced to a single segment (PI. XIIIa. fig. 10), wdiich has a 
few minute serrations along the inner edge, but they are neither so well marked 
nor so numerous as posteriorly. The latter (tip) gradually becomes longer toward the 
posterior extremity of the body, and shows many minute serrations along its edge, but 
it never assumes the many-jointed condition seen in the first foot. The rows of spikes 
at the distal end of the shaft also become very conspicuous toward the tip of the tail. 
Each foot (PI. XXIII. fig. 6) bears on the prominences above its base a branchial cirrus 
with long cilia, and one or two ciliated cups along the superior border. Moreover, on 
the side of the body there are, in addition, a few minute top-shaped ciliated processes. 
The ventral cirrus is filiform and slender, and, behind the anterior sixth, reaches the 
base of the ventral bristles. 
The speeimen is a female, and is distended with ova posteriorly. 
In the structure of the body- wall this form approaches Eulepis, and diverges from 
both Sthenelais and Sigalion. The ventral longitudinal muscles are less bulky and rounded 
than in the two genera mentioned, and, moreover, the outer border folds upward and 
forms a distinct spiral arrangement, and there is a special disposition of the dorsal longi- 
tudinal muscles, the inner or lower lobe of which is pinnate in transverse section,- so that 
three lobes appear. The nerve-area is bke that of the Polynoidse and Eulepis, in having 
a free space between the oblique muscles. The cords are much flattened, and the 
hypodermic area between them and the dense cuticle is very narrow. A transverse 
band of connective tissue and fibres passes over the cords, and a granular pigment-patch 
occurs at the inner border of each ventral longitudinal muscle, from which it thins off 
