258 PROCEEDINGS OF THE ACADEMY OF [April, 



the remainder is broadly winged on both sides. The barbs are very 

 delicate and are absent from an acute foliaceous tip about 2 mm. long. 

 Eyes are totally wanting. 



A collar of the form typical of the genus rises to a height of two and 

 one-half times the length of the segment which follows it. The dorsal 

 ends are refolded into the dorsal sinus and a slight notch occurs in a 

 median ventral position ; otherwise it is quite simple. The very small 

 tentacles are shorter than the diameter of the body. 



Nine segments, 8 of which are setigerous, form the thorax and 51 

 segments the abdomen. For nearly its entire length the body is 

 cylindrical and of almost uniform diameter, but in the posterior fourth 

 becomes somewhat broader and depressed before tapering rapidly to 

 the caudal end. No distinct glandular ventral plates are developed, 

 but all of the thoracic and the anterior three or four abdominal 

 segments are completely encircled by a thick glandular layer. The 

 thoracic and a few anterior abdominal segments are strongly biannulate, 

 the middle abdominal are simple and half as long as wide, while the 

 posterior are much shorter and more crowded. The fecal groove is 

 distinct on the caudal fourth of the abdomen, and conspicuous on a 

 few anterior abdominal segments, also where it passes obliquely around 

 the right side of the first abdominal segment and on the dorsum of 

 the thorax ; elsewhere it is faint or absent. A few small ova are present 

 in the coelom. Every portion of this worm is white, without a trace 

 of pigment anywhere. 



All setse tufts are short but rather prominent ; uncinigerous tori are 

 also short and nearly uniform, diminishing only slowly and regularly 

 from the first to the last. The setse and uncini are all delicate and 

 colorless. The collar fascicle consists of a small number of narrowly 

 winged, acute, capillary setse. Remaining thoracic somites have a 

 larger number of partly capillary, partly spatulate setse placed be- 

 tween two small lappet-like processes. The former consist of a dorsal 

 row of acute tapering setae with one moderately wide and one just 

 perceptible wing and a small number of very small and inconspicuous 

 crooked setse (fig. 62) with rudimentary wings found below the spatu- 

 lated setse. The spatulate setse (fig. 64) are arranged in two rows of 

 about ten each; they have delicate, striated, usually symmetrical, 

 obovate blades, and long very slender mucronate processes. The 

 abdominal setse (fig. 63) are also in one series, few in number, rather 

 coarser than the thoracic and with the two wings narrow and about 

 equally developed. Thoracic uncini contain a single series of erect 

 crochets or hooked setae (fig. 65) with striated stems and the slightly 

 enlarged head thrown back, a large coarsely divided crest and stout> 



