1906.] NATURAL SCIENCES OF PHILADELPHIA. 251 



cesses with somewhat constricted stalks standing midway between 

 the branchiae and the neuropodial setae tuft. After the first abdominal 

 segment the neuropodial cirrus quickly becomes reduced and in four 

 or five segments has become quite rudimentary or totally absent. 



The caudal or fecal tube has already been partly described. It is 

 very delicate and thin-walled and bears no trace whatever of para- 

 podia. Along its ventral side, however, what appear to be nerve 

 ganglia can be distinctly seen and counted through the body wall, 

 and delicate lines running in pairs from their neighborhood dorsad 

 and cephalad have the same metameric arrangement. 



The type specimen is richly colored. The outer whorl of paleoli are 

 a warm golden, the inner a golden brown. The thoracic region is a 

 rich sienna brown, especially deep on the dorsal interbranchial region 

 of the peristomium as well as of succeeding segments, and on the sides 

 of the latter and the first ventral plate. The ventral post-branchial 

 lobe of I and the dorsal branchiae are also well colored, but other cirri 

 are pale. The gill filaments are pale purple, each with a deep brown 

 basal spot. This specimen is a male, and the abdomen is colored pale 

 cream from the contained sperm. Except for delicate lines formed 

 of minute dots of reddish browm, which begin at the ventral setae tufts 

 and then pass dorsad along the anterior margin of the segment and in 

 most cases continue on to the antero-lateral margin of the gill, there is 

 no pigment in this region. The intestine is filled with a greenish-gray 

 matter that colors the fecal tube. Most of the other specimens are 

 paler, but one has the anterior brown parts of a deep chocolate. The 

 genital products escape by means of a pair of openings through the 

 body walls behind the parapodia of each segment and in several cases 

 from large masses within the tubes. 



The opercular paleoli vary from bright yellow to the more usual 

 deep golden brown. They are all very stout, hard and rigid, and of 

 peculiar irregular forms difficult of accurate description. All have 

 slender, elongated stems, smooth superficially but striated longi- 

 tudinally at the core, bearing very hea^•y and strong external blades, 

 the great part of whose surface is roughened by numerous fine wavy 

 parallel ridges w^hich are slightly imbricated with their edges directed 

 outward. The markings are not shown in the figures. 



The outer whorl of normal opercula contains from 39 to 64, according 

 to the size of the worm, between 50 and 60 being the most usual num- 

 ber. They are arranged in two symmetrical groups, though there 

 appears to be a decided tendency for the right half to include one or 

 two more than the left. Exclusive of the stem they (fig. 45o) consist 



