ChiTetopterus Variopedatns. 483 



animal to shrink to one end of the tube makes it difficult to remove 

 it without danger of injury when any sharp instrument is used. 



^\^len the tube is opened the animal is found attached to the inner 

 wall by three adhesive discs. These are on the ventral side of three 

 successive segments posterior to the region of the body which is fre- 

 quently mistaken for the "head," but which is the anterior region 

 of the body fused with an inconspicuous head. 



The most noticeable features in the worm are the extreme delicacy 

 of its tissues and the great diversity in the form of its segments. 

 I'hey are so much unlike those found among others of the polychfete 

 annelids that it would seem, at first sight, to be impossible to show 

 the homologies between the different regions. This, however, has 

 been done by Joyeux-Laffuie. 



Cha:^topterus, like all the other polychpete annelids, is made up of 

 a number of seg-ments which varies considerably with the age of the 

 individuals. There is, withal, such a similarity among the segments 

 in several portions of the body that they may be considered in three 

 groups, as Joyeux-Laffuie has done. The anterior region consists 

 of eleven segments (based by Laffuie upon the study of the nervous 

 system) of wdiich the last nine are setigerous segments. The middle 

 region consists of five segments and the posterior region has from two, 

 in the youngest individual, to fifty in the largest specimen. 



The dorsal side of the body (Figs. 3, 4 and 5) may be distinguished 

 from the ventral by the presence of the very evident ciliated groove 

 which arises directly back of the dorsal lip of the buccal funnel and 

 extends to the mid-dorsal line of the first segment of the middle 

 region. It also bears a pair of tentacular cirri at the anterior end of 

 the superior region, and large aliform appendages on the first seg- 

 ment of the middle region (12th segment). The fourteenth, fifteenth 

 and sixteenth segments (3d, 4th and 5th in middle region) have the 

 form of palettes, but each of the segments of the posterior region 

 bears a pair of conical notopodia which are directed dorsalwards. 



The ventral (Fig. 6) side is broader and more muscular in the 

 anterior region than any other region of the animal. The ventral 

 side of the fourth setigerous segment (6th segment) bears black club- 

 shaped setfe, which give this region of the body the appearance of 



