EUNICIDAE 



149 



cirrus, and at the apex of the foot three small, retractile, papilliform lobes. Behind the 

 first three chaetigers the feet are of the normal onuphid form. The ventral cirrus is 

 transformed into a pad by the 6th chaetiger, and the prolongation of the hinder lip of 

 the chaeta-sac disappears by the loth chaetiger. The gills begin at the loth-iith 

 chaetiger and at the 20th are bifilamentous. None of my material shows more than two 

 filaments. The fully developed gill is two or three times as long as the dorsal cirrus. 



•IMM 



8mm 



K 



K 



Fig. 27. Rhamphobrachium ehlersi. 



a. Bristle from first foot. b. Bristle from third foot. 



c. Bristle from third foot, highly magnified. 



The bristles of the first three modified chaetigers are extremely long. Those of the 

 first chaetiger are capillary with hooked tips, there being a suggestion of a false joint 

 just below the hook (Fig. 27 a). Those of the 3rd chaetiger are of similar general struc- 

 ture, but the shaft carries two alternating rows of long spines which cease at a kind of 

 notch which is situated a short distance below the hook (Fig. 27 b, c). The 4th and suc- 

 ceeding feet are supported by three long pointed yellow acicula. The 4th foot has 

 dorsally capillary bristles and ventrally compound bristles with knife-like blades. At 

 the loth foot there are in addition several comb-chaetae. At about the 20th foot a pair 

 of yellow hooded bidentate subacicular hooks appear and take the place of the com- 

 pound bristles. 



The dental formula is 7 — 9:9 + 6 — 6. 



