OP THE 'POECUPINB' EXPEDITIONS. 399 



The species is roughly distingaished from U. impar by the deep brownish hue of the 

 dorsum, by the minute and rather indistinct eyes and the brownish purple proboscis, by 

 the structure of the tips of the ventral bristles and their greater delicacy, and by the 

 longer and more delicate dorsal bristles, which give the observer quite a different im- 

 pression, though somewhat difficult to describe in words. 



The head has the same form as in E. impar, and is pale throughout, no pigment 

 occurring at the base of the tentacle. The eyes appear only as minute black points ; 

 two lie at the posterior border of the head, almost hidden by the collar ; two (of the 

 same minute size) are situated to the front and outside these, as in the ordinary species. 

 The tentacle is absent ; antennae pale and filiform ; palpi pale with filiform tips ; 

 tentacular cirri absent. A single reniform scale occurred in the vessel. It had long 

 clavate papillae on the usual surface and border, thinly distributed. The dorsal 

 cirrus has a filiform tip without enlargement, and rather long clavate papillae, sparsely 

 distributed. The ventral cirrus has also a filiform tip, slightly enlarged (probably from 

 the spirit) at the end, and with short clavate papillae. It reaches considerably beyond 

 the base of the lowest bristles. 



The dorsal branch of the foot bears bristles of a similar character to those of E. im- 

 par, but they are on the whole longer and more slender, with better-marked spinous 

 rows. The smooth portion at the tip, again, is decidedly shorter than in the common 

 species. The tip, moreover, shows a characteristic conformation in some cases, having 

 a slight mucro at the termination, then a shallow notch, and another elevation or faint 

 mucro a little above the first row of spikes. One of the stronger bristles is represented 

 in PI. LXXI. fig. 13. A long clear shaft projects beyond the fleshy part of the foot 

 before the rows of spikes appear; so that the bristles are comparatively long. The 

 tendency to differentiation of the tip is observed in fig. 14 (from another strong 

 bristle). The superior edge of the ventral series has a few with tips so attenuate 

 that it is difficult to make out their structure ; the bifid condition, however, ap- 

 pears to be present. The next lower series have much longer and stronger tips; 

 and though the extremity is extremely delicate and translucent, the bifid condition is 

 apparent. The terminal hook is short, and very slightly curved; and the secondary 

 process is rather short and broad, and passes far up. The rows of spines are distant and 

 well marked. The tips of the succeeding (lower) bristles become broader and shorter ; but 

 the character of the termination remains the same. All are very translucent and deli- 

 cate. Toward the inferior edge the tip is simple, only a faintly developed hook being 

 present. One of the elongated forms near the dorsal edge of the fascicle is shown in 

 PI. LXXI. fig. 15. The arrangement of the spines and the short bifid tip are character- 

 istic. Fig. 16 represents a bristle from the middle of the foot; it is exceedingly trans- 

 lucent and very faintly serrated. A more highly magnified tip, corresponding to each 

 kind, is given in fig. 17 (corresponding to fig. 15) and in fig. 18 (corresponding to fig. 16). 



It is curious that in both examples of the species the proboscis is extruded. From 



