190«J.] ' NATURAL SCIENCES OF PHILADELPHIA. 343 



meats arched above, flattened below with a sHght neural ridge, dis- 

 tinctly biannulate dorsally with small intersegmental rings. Pygidium 

 a very small, slightly thickened and rugous ring. 



Normal setigerous parapodia (PI. XVI, fig. 22) begin on III, 

 but a small tubercle bearing a few setse lies between the cirri of II. 

 They arise at the ventral level of the segments and are prominent, 

 being from more than one-third to one-half the width of their segments. 

 Neuropodium somewhat compressed, supported by a single aciculum, 

 the postsetal lobe nearly obsolete, presetal well developed, divided by 

 an acicular notch into a supra- and a subacicular lobe, both rounded on 

 anterior but bluntly pointed on posterior parapodia. 



Neurocirri broadly foliaceous, ovate with bluntly pointed tip and 

 oblique base attached to a low cirrophore, reaching to or beyond end 

 of neuropodium which they exceed in width and overlap and conceal 

 from behind. They are relatively much larger on anterior somites 

 where they equal one-half the notocirri, diminishing to one-fourth the 

 notocirri posteriorly. Notocirrophores low and broad. Notocirro- 

 styles (PI. XVI, fig. 22) of moderate size, broadly foliaceous and im- 

 bricated over bases of parapodia, leaving most of the dorsimi of body 

 exposed. They are broadly cordate with blunt apex and nearh" 

 symmetrical base, the anterior ones broader, often wider than long and 

 blunter, the posterior tending to more acute, cimeate, longer, less 

 cordate forms, with the length as much as one and one-third times the 

 width. 



Aciculum single, yellow, stout, tapered, straight or slightly curved 

 and ending in a simple blunt point at the acicular notch. Sette in a 

 single vertical series spreading fanwise and only very slightly separated 

 at the acicular notch into supra- and subacicular groups. On the 

 type they are distiibuted as follows: somite X, 13 supra- and 21 sub- 

 acicular; XXV, 14 and 25; L, 11 and 24; LXXV, 11 and 17; and C, 

 8 and 14. 



They are nearly colorless^ with slender slightly curved stems scarcely 

 enlarged at the ends (PI. XVI, fig. 23) to form an imperfect asymmetri- 

 cal socket, the best developed side of which is broadly rounded and 

 provided with a uniform series of slender teeth. Appendages of 

 moderate length, very uniformly about one-half depth of neuropodium, 

 rather broad at base but tapering to a slender tip with scarcely dis- 

 cernible marginal denticulation. 



Color uniform dark brown, yellowish l^rown or pale yellow with a 

 few irregularly scattered dusky or black blotches, one of which may 

 be on the prostomium. 



