440 THE ANNELIDA POLYCHAETA. 



narrower than more proximally. In profile there appear on the crown four or 

 five slender teeth above the short fang. The fang is scarcely curved; its distal 

 upper edge is convex, its lower one straight, or but slightly concave; below where 

 its lower edge meets the stalk the latter weakly bulges. The projecting caudal 

 region of the crown is higher and less widely rounded than is usual in stroemi. 

 (Plate 80, fig. 11). 



The abdominal uncini have the usual short broad base. In profile, above the 

 large tooth, there may appear either one or two smaller teeth. The crown of 

 smaller teeth bends commonly about the base of the large tooth in a single series 

 of six or seven teeth; but rarely one or more teeth are partially crowded out of 

 the series above. The characteristic form of the base is shown. (Plate 80, fig. 

 12-14). 



Localities. Between Panama and the Galapagos Islands: Sta. 4631 (lat. 

 6° 26' N., long. 81° 49' W.). Depth 774 fms. Bottom of green sand. 3 November, 

 1904. One specimen (type), of which the caudal end is lacking. 



Off Peru: Sta. 4666 (lat. 11° 55' S., long. 81° 20' W.). Depth 2,600 fms. 

 Bottom of fine grey radiolarian ooze. 18 November, 1904. One specimen. 



Ampharetidae. 



These are polychaetes of small or medium size in which the body is convex 

 above and flattened below. The body presents two regions, of which the ante- 

 rior, or thorax, is broad and the posterior, or abdomen, much narrower. The 

 thoracic division has biramous parapodia and bears both simple capillary setae 

 and uncini, while nearly always the parapodia of the abdomen are represented 

 only by the uncinigerous neuropodia, though rarely (Otanes) the notopodial 

 setae continue to the end of the body. In addition, the first one or two somites 

 are set off together with the prostomium in such a way as to present a distinct 

 anterior region apart from the rest of the thorax. A longitudinal midventral 

 groove is present along the abdomen, and lateral folds ordinarily separate the 

 dorsal from the ventral regions of the body. 



The prostomium is distinct and varied in form, the frontal region sometimes 

 expanded into a distinct lobe, which may be very prolonged (Moyanus). Below 

 this lobe the filiform tentacles, which may be either smooth or ciliated, are borne 

 about the border of the mouth, within which in most cases they are retractile. 

 Sometimes there is a distinct tentacuHferous lobe projecting below the frontal 

 one, and this may rarely be strongly extended and formed into a long proboscis 



