a ^ , DR. W. BAIRD OX A NKW BBITISH AXKEIJDE. 9 



about oue-third the whole length and is composed of 21 segments, 

 the posterior containing 85. In form it tapers gradually from 

 the head to the tail, which terminates in a blunt point without 

 cirri. The dorsal surface is beautifully marked with dark-purple 

 spots, which extend over the upper part of the feet, leaving a 

 hollow space in the centre free from them. The anterior portion 

 of the body is convex, the lower flattened. The segments of the 

 anterior part are of considerable size, but those of the lower are 

 small and very much crowded together. A canal runs down the 

 ventral surface the whole length, while a similar one rvms down 

 the dorsal sui'face of the anterior portion only, beginning at the 

 sixth or seventh segment and continuing to the twenty -first. The 

 head is rather small ; the first segment of the body of moderate 

 size, and the four succeeding ones very narrow (fig. 1 J), the first 

 nearly equalling the three following. The tentacular cirri are equal 

 in length to about the four first segments. The feet of the anterior 

 portion of the body (fig. 1 a) are all simple lobulated feet, with- 

 out any foliaceous branchial lamina. The dorsal lobe is short, 

 stout, and rounded at the apex, wath a cirrus springing from near 

 its root, about one-third longer than the lobe itself, and not 

 crenated underneath. The ventral lobe is somewhat larger than 

 the dorsal, and the cirrus attached to it is very short, not quite 

 half the length of the lobe. The bristles attached to it are of 

 two kinds : those especially attached to the lobe nearest the 

 dorsal lobe (the superior fascicle) are all slender, compound, with 

 a sharp-pointed smooth style inserted into a stouter cylindrical 

 shaft which is slightly striated {setae, spinosce). The bristles of 

 the inferior branch are bifasciculate, and consist of one bundle 

 composed • of spinous bristles like those above described, and 

 another composed of etouter and rather shorter setae with a 

 striated slightly bent cylindi-ical shaft cut obliquely at the tip, 

 io which portion is articulated a short claw-like piece, quite 

 smooth, and slightly bent at the apex {setae falcated) . The aciculae 

 are stout and of a black colour. The posterior feet (fig. 1 h) are 

 all much smaller than the anterior, but more complicated in 

 structure. Above the base of the dorsal or superior lobe we find 

 a compressed foliaceous lamella. The superior setiferous tubercle 

 is also furnished with a similar lamina, but very large, extending 

 across the middle lobes of the foot. The ventral cirrus has ap- 

 pended beneath its base another foliaceous lamina of about the 

 same size as that attached to the dorsal lobe. The cirri of these 

 lobes are rather short, that of the dorsal lobe being longer than 



