polych.i;ta. — benham. 147 



The ventral shields are 13 in number ; anteriorly they are 

 transverse, rectangular ; posteriorly, square. 



The genus is characterised by three cutaneous lateral folds 

 at the anterior end belonging to as many segments. 



The prostomium is produced into a dorsal thin upper lip, 

 with an undulating margin, behind which is the tentacular 

 ridge which extends downwards at each side nearly to the 

 lower hp (Pi. xlvii., figs. 26-28). The tentacles appear short, 

 but were so intertwined that it was impossible to measure 

 them. There are no eyes or pigment spots. The peristo- 

 mium is produced laterally and ventrally into a large thickish 

 fold, broader laterally, where its edge is reflected ; narrow 

 ventrally, allowing the rectangular lower lip to be seen (PI. 

 xlvii., figs. 26-27). 



The second segment and the next are fused together. 



I follow Ehlers in this analysis of the region as given for 



Terrebella {Scione) cefrafaA 



On what is probably the 3rd segment is the single pair of 

 arborescent gills, \\ hich spring from a nearly vertical wall in 

 front of the first chsetigerous segment (PI. xlvii., figs. 26-28). 

 From the hinder margin of this branchial segment rises the 

 second lateral cutaneous flap, which extends downwards to 

 the level of the lower edge of the tori uncinigeri of the follow- 

 ing segments, but does not extend across the ventral surface. 



The third fold, which springs from the hinder portion of the 

 first chsetigerous, is of less width but of the same extent as 

 the second. 



The arborescent gill has a thick stem Avhich bears a few 

 short thick branches, which in their turn divide again into 

 a niimber of short twigs, so that the gill itself appears as a 

 mass of densely aggregated branches. 



In front of the base of each gill is a small conical prominence 

 projecting forwards, and carrying at its apex a narrow 

 cylindrical process, which is inclined outwards (PI. xlvii., fig. 

 28). (Are these the representatives of a second, anterior, 

 pair of gills ?) 



The uncini commence on the second cheetigerous segment 

 as usual, and the first six are uniserial ; but on the 7th and 

 on the eight following segments they have an " alternate " 

 arrangement. Those in the abdomen, however, are again 

 uniserial, all the points being turned in the same direction. 



]. Ehlers— Florida Anneliden, 1887, p. 248. 



