1885.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 437 



The first seven pairs of parapodia are smaller than the following^ 

 ones, but are two-branched ; the lower branch is divided into distinct, 

 terminal lobes, and bears a ventral cirruSand a small fascicle of setsej 

 the upjier branch is swollen, papilliforro, and turned upward. The suc- 

 ceeding- segments of the anterior region increase successively in size, 

 and bear larger parapodia. These parapodia have a long, ligulate ven- 

 tral cirrus, longer than the setigerons lobe; the setigerous portion 

 bears two groups of seta3, and is divided into three tapering lobes, two 

 of which terminate the anterior lip and are smaller than the posterior 

 lip. At about the fifty-eighth segment the small, acute, papilliform, 

 superior lobe appears ; this contains a small fascicle of short setae. Aris- 

 ing from the superior side of the parapodia, close to the base, there is 

 an elongated, flattened, tapering, acute, ligulate process, with the tip 

 directed upward; this is similar to the ventral cirrus in size and length. 

 Farther back, beyond the seventy-fifth segment, the upper dorsal ligula 

 develops a lobe or auricle on its upper side, near the base, which be- 

 comes more prominent further back, where the terminal portion of the 

 ligula becomes reduced in size. At about the ninetieth segment there 

 is an abrupt change in the form and size of the body and parapodia; be- 

 yond this point the segments are much broader and more depressed ; 

 the median dorsal field is smooth and nearly continuous, and nearly 

 similar to that of the anterior region, each segment being marked by two 

 distinct transverse lines ; the lateral fields above the parapodia are broad 

 and deeply incised between the segments. 



The ventral surface has, as in the anterior region, a broad and deep, 

 concave groove, bordered on each side by a raised, rounded ridge ; the 

 lateral portion is much more prominent than on the anterior region. 

 The parapodia of this region are prominently two-branched, the ventral 

 branch being much larger, and separated from the dorsal branch by a 

 rather wide, rounded interval, appearing like a furrow along the sides; 

 the dorsal branch consists of a swollen, conical, setigerous lobe, bearing 

 a broad cluster of very slender sette arising somewhat in two groups, 

 and a broad, swollen, dorsal ligula, with a distinct lobe at the base on 

 the dorsal side, and a prominent, papilliform tip. The inferior branch 

 has a large, prominent setigerous lobe, divided at the end into two 

 distinct, tapering, acute, anterior lips, and abroad, flattened, spatulate, 

 posterior lip, terminating in a small, central, acute papilla; between 

 these lips is a broad, fan-shaped fascicle of slender, capillary setse, much 

 longer than those of the dorsal branch. The ventral ligula is as long 

 as the setigerous lobe and arises from about the middle of the lower 

 edge ; it is swollen at the base, flattened toward the end, somewhat 

 falcate, taj^ering to near the end, which is obliquely subtruucate and 

 ends in a small papilliform tip. Close to the base of the i^arapodia and 

 at some distance from the ligula there is a very small papilliform organ. 

 Towards the posterior end of the body this becomes larger and more 

 prominent. The posterior j)arapodia have the dorsal branch nearly as 



