240 PROCEEDINGS OF THE ACADEMY OF [Vol. LXXV 



pair on the other hand are enlarged, being fully four times the 

 diameter of the next largest. The separate facets can be detected 

 easily under a magnification of four or five diameters. 



Collar well preserved, prominent and flaring. Starting as a 

 broad fold at the second fascicle of setae its margin runs straight 

 forward, enclosing the collar fascicle, anterior to which it bends 

 ventrad at a rounded right angle and then continues of even height 

 to a level ventrad of the thoracic tori where it is produced into 

 a pair of triangular lobes as long as the first two somites and pro- 

 jecting forward in mutual contact. On each side of a median 

 dorsal cleft is a broadlj^-rounded dorsal lobe, united with the body 

 of the collar by a thin membrane dorsal to the collar setae, with 

 which it forms a pocket. 



Oral membranes foliaceous, reflexed onto the branchial base. 

 Tentacles a pair of foliaceous, vertical folds, slightly exceeding 

 the oral membranes in length and bearing a terminal filament 

 nearly as long as the broad basal portion. 



Thorax distinctly depressed, about two -thirds as deep as wide, 

 becoming narrower caudad. Segments well marked, the ratio of 

 length to width varying from 1:3 anteriorly to 1.2 posteriorly. 

 Thoracic portion of fecal groove nearly obsolete. Ventral plates 8, 

 well developed, separated from the parapodia laterally by a con- 

 tinuous groove, all nearly square except the last which has the 

 right posterior corner cut off. Parapodia well marked, formed of 

 prominent dorsal setigerous papillae and immediately ventral to 

 these transverse tori nearly uniformly one-eighth the circumference 

 of the segment. 



Abdomen subterete, of nearly uniform diameter almost to the 

 tapered caudal end. Anterior segments similar to posterior 

 thoracic segments, becoming regularly shorter until they are four 

 or five times as wide as long. Ventral plates thick and well marked, 

 divided into equal halves by a deep fecal groove. They remain 

 of uniform width and consequently the anterior ones are nearly 

 square and the posterior about four times as wide as long. 



Ground color of body pale, the dorsum of the abdomen much 

 tinged with brown and a pair of conspicuous brown spots occupying 

 the third, fourth and fifth segments dorsal to the setae. Lighter 

 brown spots occur between the parapodia also and other parts of 

 the body are tinged with brown. The gills are pale, marked with 

 five zones of deep brown usually equal in width to the intervals 

 separating them, the first close to the base, the last about its own 

 width from the tip. Different gills vary greatly, some being almost 

 colorless, others with deep pigmentation covering solidly sections 

 of the radiole and entire barbs arising at that point. Narrow 

 dashes of pigment also mark the intervals between the barbs on 

 the base. 



Setae all colorless or nearly so. Thoracic tufts rather prominent 

 but too much broken on this specimen for full description. Those 



I 



