232 PROCEEDINGS OF THE ACADEMY OF [April, 



The exact form of the prostomium and mouth is not apparent, inas- 

 much as this region is retracted, leaving a conspicuous trifid opening 

 which has been sometimes indicated in descriptions of other species as 

 the true mouth. In this condition the peristomium is trilobate. All of 

 the segments are simple rings, separated from one another by clearly 

 defined but not conspicuous intersegmental furrows which become 

 more distinct posteriorly. The segments pass regularly into one 

 another without any conspicuous breaks in contour, and increase in 

 length, as they do in diameter, to about XII, then undergo little change 

 to the middle of the body, behind which they become again gradually 

 shorter. Toward the posterior end they diminish to a minute pygi- 

 dium which contains a small, vertical, slit-like anus, but appears to 

 lack cirri or other appendages. 



The number of segments varies from 31 to 33, the latter number 

 being present in the type. All, including the peristomium, bear both 

 notopodial and neuropodial setse in tufts upon minute tubercles. 



The chief characteristic of the species is the richness of its papillation. 

 The entire dorsal surface is thickly covered with filiform papillae espe- 

 cially numerous toward the ends, where they are so densely arranged 

 that they actually touch and crowd one another. On the middle 

 segments they are more widely separated, but are still so numerous 

 that where Brada villosa bears 3 or 4 in the length of a somite, this 

 species bears 8 to 12, They are not disposed in regular rows, but are 

 arranged more or less irregularly at nearly equal intervals in all direc- 

 tions. The intersegmental furrows lack papillae and appear as smooth 

 lines, like narrow avenues through a grass field. Just anterior to each 

 parapodium the papillae become few or nearly disappear, leaving a 

 wider open space at this point. Those papillae remaining in this 

 region are collected about the setigerous tubercles, but instead of be- 

 coming enlarged and forming rosettes they are actually smaller than 

 the dorsal ones. 



All of the papillae (fig. 14) are slender, elongated and filiform with 

 a small terminal knob. Many of them collect a thick girdle of sedi- 

 ment in a zone near the base, which gives the appearance of a bulbous 

 enlargement. They differ considerably in length and toward the 

 anterior end of the body exceed the length of the segment bearing 

 them, so that this region has the appearance of being thickly coated 

 with fine hairs. At the level of the ventral margin of the neuropodial 

 tubercles the dorsal papillation ceases abruptly, and is replaced by 

 the much smaller papillae (fig. 15) which cover this surface. Although 

 their number is nearly as great, these papillae are so much smaller than 



