1909.] NATURAL SCIENCES OF PHILADELPHIA. 291 



tips. A double rank of numerous pinnae or filaments arises along the 

 inner or apical face of the rachises and continues nearly to their tips ; 

 the longest of these scarcely exceed the greater diameter of the rachises 

 and they diminish in length distally. 



Tentacles lanceolate, foliaceous, about as long as the diameter of 

 the branchial bases, to the ventral side of which they are attached. 

 Just within them, enclosing the mouth and about one-third as high 

 as the inter branchial membrane, are the oral membranes, which like 

 the tentacles are detached with the branchial crowns. Mouth trans- 

 verse, its corners bounded above by a low rounded elevation, from 

 between which a tongue-shaped process projects over the mouth. 

 Ventral to it is a soft irregular lip, and below this again a much larger 

 firm triangular lip. 



Thorax depressed, broader anteriorly than posteriorly and regularly 

 tapered caudally. Segments eight, all but the peristomium setigerous ; 

 intersegmental furrows obsolete. Thoracic mantle thin and greatly 

 developed, embracing all of the setae tufts and extending beyond them 

 to a width fully equal to that of the thorax. Though folded and 

 somewhat tufted between the fascicles of setae the margin of the mem- 

 brane appears to be entire and not scalloped. Its cephalic border is 

 divided into a pair of dorsal setal lobes, enclosing the collar seta tufts, 

 and a ventral pair of branchial lobes. The median notch separating the 

 latter is wide and shallow, the lateral notches, on the contrary, being 

 deep and narrow. The posterior fold or apron is thicker, has an 

 extensive glandular area and projects only slightly as a broad median 

 ventral lobe. There is a broad but shallow and rather ill-defined 

 dorsal thoracic groove and an annular groove, somewhat distinct on 

 the dorsum, separating the thorax and abdomen. 



Abdomen rather soft, broadly rounded laterally, slightly depressed, 

 tapered gently to the pygidium and divided into dorsal, lateral or 

 parapodial, and ventral or neural fields, the latter being marked by a 

 broad, open fecal groove. Abdominal segments numerous, very 

 short, much crowded, and distinctly indicated by the extensive tori 

 only. Integument of dorsal and ventral surfaces more or less swollen 

 and wrinkled, probably in part due to the preserving fluid. A cal- 

 careous incrustation occupies a nearly circular area on the dorsum 

 of the caudal end, which is bluntly rounded and terminated by a very 

 short pygidium containing a large, vertical, slit-like anus guarded 

 by somewhat tumid lips. 



Thoracic setae form seven compact flattened tufts, somewhat spread- 

 ing distally, of very numerous setae; they project obliquely dorsad 



