NEREIDAE. 191 



or even a little wider in front of the anterior eyes than at base. Notched above 

 in the median line at base and longitudinally furrowed in front of the notch, 

 with a sulcus bending out toward each anterior eye and a quadrate figure in 

 front of this outlined by sulci. The unpaired tentacle inserted in the caudal 

 region, as usual, and lying in the median furrow. 



On each side there are the bases of eight tentacular cirri, all having been 

 broken off so that their lengths cannot be determined; but the bases of the 

 upper ones are much the stoutest, and of these the second from the most pos- 

 terior is thickest and the most anterior one smallest. 



First three parapodia with only neuropodium and neuropodial setae. Those 

 succeeding have, in addition, a notopodium which appears as a tubercle on the 

 dorsal side at the base of the neuropodium, this bearing finer, simple capillaiy 

 setae in contrast with the usual compound setae of the neuropodium. The 

 cirri are all broken off near the base. The bases of the first four pairs of noto- 

 cirri are conspicuously thicker than those following and of these the cirri of the 

 first pair are stoutest, being of nearly the same thickness as the largest of the 

 tentacular cirri. Each neuropodium bears an acutely pointed, auriculiform 

 process at its distal end above or dorsocephalad. Most notopodia are narrowed 

 to a point ventrad of the setae. 



All setae in the type are colorless and transparent, or nearly so, or in part 

 show a vague and very dilute greenish yellow cast. The capillary setae in the 

 posterior segments are numerous, the notopodial fascicles being large and con- 

 spicuous and extending beyond the distal end of the neuropodia. The tips of all 

 the neuropodial setae are missing so that their structure could not be determined. 



The proboscis, unlike that of other species recorded from the Indo-Pacific 

 region, presents near its distal rim, when extended, a half circle of conspicuous, 

 chitinized, rounded papillae, these forming a half-crown across the dorsal half 

 of the proboscis with none on the ventral half. The papillae are ten in number. 



Locality. Marshall Islands. A single specimen came up on anchor 

 from a depth of 12 fms. Albatross Exped. 1899-1900. 



This form is characterized chiefly by the half-crown of chitinous papillae 

 at the end of the proboscis, a character seeming at once to separate it from the 

 preceding and from other species of the region. 



Nereid AE. 



This is one of the most homogeneous and clearly defined families of the 

 Polychaeta, the characteristic and obvious structural appearance ordinarily 



