318 THE ANNELIDA POLYCHAETA. 



ling or a little surpassing the other setae. The acicula of the other parapodia 

 also long and similarly ending in fine tips. Similar but smaller setae occur on 

 the second and following parapodia; but, in addition, limbate setae are present 

 and a fascicle of pectinate setae that have unusually long stalks. The expanded 

 tips of the pectinate setae have the usual cuneate outUne, each being like a 

 funnel with a large sector removed, and with the free edge finely pectinate. 

 (Plate 37, fig. 9). The hmbate setae are conspicuously bent at the base of the 

 blade and the very fine tip is more or less curved, frequently hooked to some 

 extent. (Plate 37, fig. 10). Farther caudad uncinate setae, or crochets, make 

 their appearance. These are long and generally stout though varying consider- 

 ably in thickness and in the curvature at the cervix. The teeth stand at a 

 considerable angle with the axis, the upper and somewhat larger one stout and 

 considerably curved. (Plate 38, fig. 1). The setae are all proportionately 

 long. The limbate setae have the blades whitish in color so that the fascicles 

 appear white tipped, giving a characteristic appearance to the species. 



In one specimen the maxillae have the teeth whitish. In the left outer 

 plate III there are eleven teeth, on the inner thirteen. The teeth of the inner 

 plate are coarser than those of the outer one. The halves of the mandibles 

 seem to be entirely distinct, being only in weak contact. The white masticatory 

 plates stand at a strong angle to each other, each extending obliquely cephalo- 

 ectad. Each has a distinct notch on the ectal side, the plate being somewhat 

 depressed or furrowed mesad from this. The stems are widest at the anterior 

 end just caudad of the masticatory plate. (Plate 38, fig. 3). 



The somite on which the branchiae begin could not be determined. The 

 longest branchiae about equal the width of the somites. 



The tubes have the structure and appearance usual in the genus. The 

 maximum diameter at the large end is about 5.5 mm. The rings representing 

 the limits of successive layers are mostly from four to five millimeters apart. 



The color of the animals is very dark excepting a pale median dorsal and 

 a median ventral band. Some of the glandular pads are also pale. The limbate 

 setae white at tips. 



Locality. Off Mexico: Sta 3418 (lat. 16° 31' N., long. 99° 52' 30" W.). 

 Depth 660 fms. Bottom of brown sand with black specks. Bottom temp. 

 39° F. 11 April, 1891. Two specimens. 



Characterized especially by the very long first parapodia and their numer- 

 ous stout setae, and by the structure of the setae of these and the other para- 

 podia. 



