TEREBELLIDAE 



195 



As Benham states, there are two kinds of dorsal bristle, a larger kind (Fig. 80, a) 

 with one edge clearly denticulated, and a smaller kind (Fig. 80, b) with a row of minute 

 teeth on both edges. The hooks (Fig. 80, c) correspond to Benham's description, except 

 that he omits to mention the very distinct striae on the body of the hook. 



I believe the smaller type of toothed dorsal bristle to be characteristic of this species. 



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•2.mmT 



OSmTXl-r 



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a b 



Fig. 80. Polycirnts hamiltoni. 

 a. Larger kind of dorsal bristle, b. Smaller kind of dorsal bristle. 



c. Hook. 



Polycirrus hesslei, n.sp. 



St. WS 73. 6. iii. 27. 51° 01' 00" S, 58° 54' 00" W. From 51° 02' 00" S, 58° 55' 00" W to 

 51° 00' 00" S, 58° 53' 00" W. 121-130 m. Gear OTC. Bottom: fine dark sand. Eight specimens. 



Description. The largest specimen measures 70 mm. by 4 mm. for about 125 seg- 

 ments. The body is swollen and arched dorsally in the thoracic region and tapers in the 

 abdomen. The cephalic lobe (Fig. 81, a) is carried forward as a large trilobed undulating 

 membrane completely hidden by a dense tangle of long tentacles. The ventral gland 

 shields of the ist, 2nd and of the anterior part of the 3rd segments are fused into a large, 

 roughly shield-shaped mass, which in some of the examples is divided by a groove 

 corresponding in position to the anterior border of the 2nd segment. In some speci- 

 mens this groove is altogether absent. There are 10 pairs of ventral gland shields, 

 counting the reduced pairs of the 2nd and 3rd segments. These gland shields are widely 



