Dr. Johnston on British Annelides. 5 



the orifice naked : segments numerous : branchia in the form of a 

 globular tubercle over each foot^ which is uniramous ; the bristles 

 simple : tail truncate, without styles. 



Obs. The relations of this genus are rather obscure. To 

 Nephtys and Glycera it may be considered to approximate in the 

 rudimentary state of the antennae^ but in all other respects there 

 is too great a dissimilarity to allow us to consider them as very 

 nearly affined. The branchial tubercles over the feet might sug- 

 gest a comparison with Phyllodoce, but there is no structural re- 

 semblance ; the lamellae in Phyllodoce being merely modifications 

 of the superior cirrus, moveable and jointed at the base, and 

 acting as a kind of oar in the animaFs locomotion, while in Pol- 

 licita they are branchial only, being immoveable, and of no use 

 or applicability as locomotive organs. The difference in internal 

 structure is equally great, for in the one genus the organ is 

 veined with the ramifications of the blood-vessels, while in this 

 it is very distinctly areolar. I have seen one species only, which 

 may be named — 

 1. P. Peripatus. Plate II. fig. 1—6. 



Hah. In deep water amid corallines, &c. Berwick bay. 



I have seen several Irish specimens in the collections of Mr. 

 W. Thompson of Belfast. 



Desc. Worm about 2 inches long, very slender, narrowed to- 

 wards both extremities, almost cylindrical, of the usual yellowish- 

 brown colour, roughish : head small, indistinctly separated from 

 the following segment, longer than broad, rounded in front, 

 where there are three unjointed antennce, the medial nearly as 

 long as the lateral ; on the sides of the head there are besides a 

 few minute fleshy papillae, and the feet advance on each side 

 rather before the eyes, which are placed unusually backwards : 

 eyes small, four, the anterior pair most approximate : mouth in- 

 ferior : proboscis exsertile, large, smooth, emandibulate, the ori- 

 fice plain : segments numerous, about the length of their own 

 diameter, each of them furnished with a globose lamella or 

 branchial tubercle on each side placed over and above the foot, 

 immoveable, unjointed, smooth, with a small papillary tip : feet 

 about sixty pairs, one pair to every segment, conoid, uniramous, 

 papillary, not projecting beyond the branchiae when at rest, but 

 capable of being protruded beyond them, armed with four or five 

 bristles and a spine ; the bristles simple, sharp, curved like a 

 hedge-knife, altogether retractile : the skin is covered with minute 

 papillae or granules, only visible under a high magnifier : anal seg- 

 ment truncate, without styles, but on each side there is a mam- 

 millary foot, which is larger than the penultimate, and, like it, 

 appears to be destitute of bristles. 



