1905.] NATURAL SCIENCES OF PHILADELPHIA, 547 



the differences in the sculpturing and form of the papilla:; and the char- 

 acter of the neuropodial cirri become more marked. Many of the speci- 

 mens are of a nearly black color. 

 Ninoe simpla sp. nov. PI. XXXV, fig. 30; XXXVI, figs. 39-44. 



This species has much the form, general aspect and usual size of 

 Ninoe nigripes ^^errill, but none of the examples in this collection 

 reaches the ma.Kimum size of the latter. The body is very fragile and 

 no specimen is nearly complete and none represents the caudal end. 

 The most perfect example, hence designated as the type, consists of 

 160 segments and is 24 mm. long and 1.3 mm. in diameter. Other 

 larger ones, having a diameter up to 2.5 nun., are less complete. 



The prostomium has a slightly depressed sugar-loaf shape, with a 

 length about ^ greater than the basal width. Posteriorly its median 

 dorsal portion is inserted into an overarched recess of the peristomium 

 and here bears a pair of minute brown eyespots, behind which one or 

 two others are sometimes visible. Within this same recess, but some- 

 times projecting slightly beyond the peristomial fold, is a minute 

 mammiliform process (median tentacle) with a thickened base em- 

 braced by a pair of slight lateral folds. Two symmetrical dorso-lateral 

 longitudinal grooves join the sides of this recess posteriorly, and proba- 

 bly enter the deep slit-like nuchal organs seen on each side by raising 

 or dissecting off the peristomial covering. A similar pair of more dis- 

 tinct ventro-lateral grooves join the ends of a deep transverse slit 

 bounding the palpi anteriorly. The palpi are a pair of small rounded 

 lobes facing each other on each side of a deep longitudinal groove and 

 sunk into a depression on the ventral surface of the prostomium or 

 between the latter and the mouth. A rather small mouth is boimded 

 anteriorly and dorsally by these palpi and posteriorly and ventrally by 

 the peristomium. 



Except for the special features already indicated the peristomhim is 

 exactly like the following segment and, also like it, is apodous. 

 Anteriorly the body is slightly flattened and increases in width to the 

 end of the branchial region, behind which it again narrows and becomes 

 perfectly terete. 



Parapodia (figs. 39 and 40) are absent from the peristomium and 

 following somite. Beginning on III they are at first small and placed 

 at a low level, but gradually rise to a middle height and become more 

 prominent in the branchial region, behind which they again decrease 

 in size, but retain the more elevated position. Throughout they are 

 uniramous, the notopodium being a mere tubercle bearing sensory hairs 

 and entered by delicate aciculae reduced to mere fibres. The prominent 



