378 THE ANNELIDA POLYCHAETA. 



the body, cylindi-ical in form, and long, its length equalling that of the suc- 

 ceeding seven somites taken together. On each side deep sulci separate off six 

 (or five in the smaller specimen) vertical bands, but the sulci are not continuous 

 with other, finer, sulci across the dorsum or with others across ventral surface, 

 which are scarcely evident in the smaller specimen, a division into rings being 

 thus incomplete and irregular. There is a longitudinal depression along the 

 lower portions of each side. In the larger specimen, a longer, broad, trapeziform 

 band in place of the triangular area in megalus is set ofT by a deeper furrow, the 

 oblique lateral furrow extending up on the side. In front of these are four 

 narrower transverse bands, the dividing sulci between which become vaguer 

 cephalad. The anterior ventral margin is widely concave. 



The first metastomial somite is larger than the succeeding ones, though not 

 fully as long as the next two taken together. Dorsally it is marked with irregu- 

 lar sulci or wrinkles, giving a coriarious appearance. The succeeding somites 

 increase gradually in width and height to the wide region of the body, but 

 increase only slightly in length. They are all wholly simple, transverse sulci 

 occurring neither above nor below. The surface of all, as preserved, is coriarious. 

 The anus is terininal and transverse, somewhat crescentic, the ventral border 

 projecting convexly dorsad. The border is divided into six lobes, a large median 

 ventral one, one at each end, and three in the arch above. 



The setigerous tubercles are widely separated, in all cases clearly exceed- 

 ing the distance between notopodium and branchia. They are distinct and 

 conical. In the broad region in front of the middle in the larger specimen the 

 tubercles are about 1.5 nam. long. They are at the opposite ends of distinct 

 vertical ridges, which are not extended dorsad bevond the notopodium to the 

 branchia as they are in the case of megalus. 



The poorly preserved and much rubbed condition of the types does not per- 

 mit a whoUy satisfactory study of the setae. Mounted parapodia from sev- 

 eral regions of the body show in all cases two types of capillary setae. In each 

 notopodium on the ventral side, and in each neuropodium on the dorsal side 

 of the fascia, a number of exceedingly fine capillary setae which run out into very 

 fine tips (Plate 70, fig. 10), and, below these, more numerous, much coarser and 

 longer setae, wliich are also attenuated distad into very fine, smooth, and com- 

 monly curved tips. Below the tips along one side these setae have a close series 

 of scales or fine serrations. These setae are finely longitudinally fibrillated. 

 (Plate 70, fig. 9). In the neuropodia of the posterior region, at least, there is, 

 ventrad, of the principal setae and standing somewhat apart from them, an 



