POLYCH^TA. — BENHAM. 199 



The iiotopodial chc^tae, about 50 in number, are stouter 

 than the neuropodial, and are radiately arranged ; the 

 upper and anterior are shorter than the rest, but of the same 

 form ; they have a bkint point below which is a large number 

 of roAvs of minutely jjectinated frills (PI. xl., fig. 49). 



The neuropodial chsetae, about 70 in number, are in 7 or 

 8 tiers, with 3-6 (or even 7) in each tier (PI. xl., fig. 50) ; the 

 smaller number in the upper and lower, the larger number 

 in the middle tiers. There are some 23-25 frills in the longer 

 upper ch{Bta\ The lower chaetae have, as is usual, fewer 

 frills than the upper, and are altogether shorter. 



There is no evidence of a siibapical tooth (therefore 

 it Avould be jilaced in Malmgren's genus, Eunoa). Mor are 

 there any stout j^ectinations in the distal frill. 



The dorsal cirri are covered with short cylindrical papillae. 



The head is typically Harmothoid, but the 2)eaks are 

 rather widely separated (PI. xl., fig. 46). The prostomium 

 is longer than broad, the anterior eyes are lateral at about 

 the middle of the side, and the posterior are far back, close 

 to the hinder margin. 



The tentacles are finely ciliated, the subterminal swelling 

 feebly marked. The median tentacle is much stouter than 

 the laterals, and about twice their length. 



The palps are longer than the median, as also are the 

 peristomial cirri. The tentacles, like the cirri, are trans- 

 parent. 



Yellow chfet* are visible on the upper side of the base of 

 the peristomial cirri. 



Remarks. — MTntosh described in the "' Challenger " Report 

 a s])ecies. Eunoa ahyssorum, from the south of Australia, in 

 2000 fathoms, which in some respects seems to resemble the 

 ]iresent spe(;ies. But as that individual had no elytra, and 

 as the chaeta? differ in some details, and the form was eyeless, 

 it seemed desirable to establish a new species for it. 



In Eunoa opalina, from the Strait of Magellan, MTntosh 

 describes and figures " soft papillae " on the elytra, but they 

 are short and broad. He refers also to the "pellucid" 

 tentacles, and the widely separated peaks of the prostomium. 



But his figures of the chaetae show differences in that the 

 apex of the neuropodial is much more hooked and sharper 

 at the tip, and that of the notopodial is longer and sharper 

 than in the present. 



