274 NEREIS PELAGICA. 



curved shafts have short tips. The conical setigerous region is less prominent than the 

 dorsal lobes. The ventral lobe is also pointed and more prominent than the setigerous 

 region. The cirrus is shorter than the latter, and the foot generally is less massive. 



The fifty-seventh foot (Plate LXXI, fig. 7 c) has considerably diminished in general 

 bulk, and the lobes are more acute. This diminution and increased transparency make 

 both the spines and bristles very prominent in mounted preparations ; the deep black of 

 the former and the golden hue of the stout bristles with the short tips are characteristic. 

 Both dorsal and ventral cirri are proportionally longer and more slender, the former, as 

 in the thirty- seventh foot, far exceeding the latter. While this foot closely resembles in 

 general configuration the thirty-seventh, except that the dorsal cirrus is longer, and the 

 proportions of the two upper lobes are in contrast with the lower, the bristles with the 

 short tips both in the upper and lower groups are proportionally stronger. 



An interesting account of the minute structure of the bristles of this species is given 

 by Schepotielf, 1 who shows that the rows of cross-bars are continuous with the upper 

 longitudinal streaks. 



Just in front of the tail the foot presents a still further diminution in size, the hump 

 of the dorsal outline at the base of the cirrus is marked, the upper lobe is smaller, and it 

 and the others have less acute tips. The dorsal cirrus is much lengthened, and the 

 ventral projects beyond the adjoining lobe. The vascularity of the foot generally is 

 well shown in these translucent organs. The bristles retain the characters already 

 indicated. 



In this species the ventral longitudinal muscles are more elongated transversely, and 

 have a longer and more pointed dorsal (external) fold than in Nereis diversicolor. 



In a specimen from St. Andrews in which injury had occurred, the third and fourth 

 feet of the right side were in process of reproduction. In these the dorsal and ventral 

 cirri were proportionally large, appearing more conspicuous than the lobes, yet all were 

 new. Many examples show reproduction of the tail. Prof. Jeffrey Bell, again, has 

 recorded an example from Guernsey in which the tail was bifid. 



Habits. — Though the majority of examples obtained from deep water off St. Andrews 

 are small, very few reaching medium size, large specimens are found in the stomach of 

 the cod and also in that of the flounder. In the whole series of British examples no finer 

 ones occur than those from St. Andrews. The other features in the habits of this form 

 are indicated under those of the family. 



This species has been supposed to bore in wood and also in telegraph cables. Thus 

 Dr. Carpenter forwarded a specimen of medium size along with a portion of a telegraph 

 cable (1874). So far as could be observed, however, the perforations were due to other 

 forms. 



Reproduction. — Specimens having the general form of Iphinereis fucicola, (Erst, are 

 not infrequently met with at low water early in February, or even as early as the 18th 

 January. The anterior region of the body resembles that of Nereis pelagica typica, only the 

 head and palpi are of a richer green with a slight tint of blue, and the tentacles are bluish- 

 green, thus contrasting with the dull orange proboscis, which is beautifully marbled or 

 cut into areas by pale streaks. The terminal processes of the palpi are paler. The 

 1 ' Zeitschr. f. wiss. Zool./ Bd. lxxiv, p. 21, Taf. xxxiv, figs. 5—15, 1903. 



