Annelides. 9631 



Nereis obtained in the sea-water mud deposits) had been observed in the neighbour- 

 hood of the wharves and pontoon at Milbay, Plymouth, and which were described to 

 me as swimming about in large companies on the surface of the water. I hastened to 

 investigate the subject myself, and obtained some of the creature*, which I carefully 

 preserved in spirits, and Mr. J. B.Rowe, of the Plymouth In>titution,has prouuunced 

 them to belong t) the genus Heterouereis, the species H. longissima ; the habitat, 

 according to Johnson, being the coast of Ireland. Finding ihem to be so very un- 

 common), a few were sent to the British Museum, and the Natural History authorities 

 there confiimeU the preceding view. Their visit to Plymouth was of a very transient 

 character, as they have now entirely disappeared, and it is this fact that induces me to 

 draw attention to the subject, as it is not impossible that similar visits may have been 

 paid by them to other parts of the coast without exciting attention. Their sudden 

 disappearance is to me less extraordinary than their sudden appearance, for, although 

 there must have been millions of them, yet they evidently formed dainty morsels for 

 the pollack, which pursued them with great avidity. I tried them myself as bait, and 

 caught pollack with them within a few moments of casting the line over the side of 

 the boat. It is worthy of remark also that pollack within the last month have been 

 unusually abundant in Plymouth Sound, as many as ten to fifteen dozen being 

 occasionally taken by amateurs before breakfast with the ordinary pollack-flies and the 

 silver spinner. On a calm evening ihe surface of the sea, in the viciniiy of the break- 

 water, woidd be literally alive with pollack pursuing these Annelides, which were seen 

 scudding about in all directions. Their length varies from four to sixteen inches, and 

 the appearance of those which I have in my possession is not unlike that of a large 

 Nereis, or mud-worm, divided transversely into two distinct portions, the anterior half, 

 constituting the body, being more in shape like a flattened caterpillar, and of a pale 

 delicate flesh-colour, whilst the posterior, forming the tail, is of a bright red, and 

 almost identical in shape with that of the Nereis. A longitudinal indentation extends 

 the entire length of the creature, both above and below. When swimming its branchiae 

 give to its sides a very curiously serrated appearance. Its motion is very rapid and 

 serpentine, the undulation being generally lateral, but some that I preserved for 

 several days alive moved also with vertical undulations like a leech. They are 

 furnished with strong forceps, with which they can puncture the skin of the fingers, 

 producing some amount of temjtorary irritation. On immersing the hand, or the point 

 of a stick, in the water near them, they immediately rushed towards it, and quickly 

 began to examine its character, from which circumstance they were easily captured in 

 large quantities. The voracity with which they attacked a piece of meat thiown in 

 amongst them was very remarkable. Their chief places of resort were the viciniiy of 

 rocks and quays, where they were seen in myriads swimming on the surface of the 

 water. They appeared to feed among the Algie growing there, and could be seen as 

 the tide receded clinging by their forceps to the Algae, and hanging down like so many 

 leeches. I found them, however, in great numbers more than 100 yards distant Iroin 

 the rocks, probably driven about by the pollack. How they were introduced here opens 

 a curious field of inquiry. So far as I can learn they were first observed in the imme- 

 diate vicinity of the pontoon used by the Irish steamers, but I cannot see my way clear 

 to assume the possibility either that any quantity of these creatures would have accom- 

 panied a steamer so far, or that their spawn could have been brought here in quantities 

 sufficient to have produced suddenly such an extensive colony. Moreover, the Irish 

 steamers have frequented that pontoon for a great number of years, and therefore might 



